Process for treating gasoline

ABSTRACT

The present application relates to a process for treating gasoline, comprising the steps of: splitting a gasoline feedstock into a light gasoline fraction and a heavy gasoline fraction; optionally, subjecting the resulting light gasoline fraction to etherification to obtain an etherified oil; contacting the heavy gasoline fraction with a mixed catalyst and subjecting it to desulfurization and aromatization in the presence of hydrogen to obtain a heavy gasoline product; wherein the mixed catalyst comprises an adsorption desulfurization catalyst and an aromatization catalyst. The process of the present application is capable of reducing the sulfur and olefin content of gasoline and at the same time increasing the octane number of the gasoline while maintaining a high yield of gasoline.

TECHNICAL FIELD

The present application relates to a process for treating gasoline, andparticularly to a process for the desulfurization of gasoline.

BACKGROUND ART

Air pollution caused by vehicle exhaust emissions is getting worse. Withthe increasing emphasis on environmental protection, countries aroundthe world have accelerated the pace of upgrading the quality of fuel forvehicles. For example, the Chinese national standard GB17930-2016requires the sulfur content of gasoline to be not more than 10 μg/g, andthe volume fraction of olefin in gasoline to be not more than 24%.

Catalytic cracking gasoline is a major component of motor gasoline,accounting for about 75% in gasoline pools, and is characterized by higholefin and sulfur content. It is not difficult to achieve deepdesulfurization of gasoline and reduce the olefin contents in catalyticcracking gasoline by hydrogenation technology. However, since olefin isa high-octane component, a great reduce of its content will lead to agreat loss of the octane number of gasoline, thereby affecting theperformance of gasoline in automobiles and the economic benefits ofrefineries. Thus, techniques for deep desulfurization of gasoline whilemaintaining the octane number of gasoline has become a hot spot in cleangasoline production.

At present, the deep desulfurization of gasoline is mainly performed byhydrodesulfurization or adsorption desulfurization.

Selective hydrodesulfurization is one of the main ways to removethiophene-based sulfides, but the saturation reaction of olefins andother reactions may also occur in large quantities, resulting in a greatloss of the octane number. In addition, the deep hydrogenation processfor restoring octane number is also approved by practitioners, whichcomprises providing a second reactor to promote the cracking,isomerization and alkylation reactions of low-octane hydrocarbons whileperforming deep desulfurization and olefin saturation, so as to achievethe goal of restoring the octane number.

Chinese patent application No. CN101845322A discloses a process forreducing the content of sulfur and olefin in gasoline, in which thecatalytic cracking gasoline feedstock is firstly treated in aprehydrogenation reactor to remove dienes, and then split byfractionation in a fractionation column into light and heavy gasolines;the light gasoline is subjected to adsorption desulfurization in thepresence of hydrogen; the heavy gasoline is subjected tohydrodesulfurization in a selective hydrogenation reactor, the resultingreaction effluent is subjected to hydro-upgrading in a hydro-upgradingreactor to reduce the olefin content, and the upgraded heavy gasoline isblended with the product resulted from the adsorption desulfurization ofthe light gasoline to obtain clean gasoline that meets the standardrequirements. The adsorption desulfurization catalyst may show a goodeffect in the removal of sulfides in gasoline, but the adsorptiondesulfurization is carried out in the presence of hydrogen, which wouldresult in the saturation of olefins in the catalytic cracking gasoline.Especially when the light gasoline is subjected to adsorptiondesulfurization, there would be a great loss of the octane number, asthe olefin component of the light gasoline has a higher octane number.

In adsorption processes for the removal of sulfur-containing compoundsin fuel oil, light oils are subjected to reaction and adsorption in thepresence of hydrogen using adsorbents, producing metal sulfides orremoving sulfur by means of the polarity of sulfides, with a lowhydrogen consumption and a high desulfurization efficiency. Gasolinewith a sulfur content below 10 μg/g can be produced. Although deepdesulfurization of gasoline can be achieved using adsorption processeswith a low hydrogen consumption, there is still a slight loss of theoctane number of the gasoline product. Especially when dealing with agasoline feedstock with high olefin content and high sulfur content, alarge loss of the octane number of gasoline would still be encountered.

For most catalytic cracking units, in order to increase the productionof propylene and butene and increase the octane number of the gasoline,an effective way is to use a catalyst or adjuvant containing a molecularsieve having an MFI structure. U.S. Pat. No. 3,758,403 discloses theaddition of ZSM-5 molecular sieves to a catalytic cracking catalyst toincrease the octane number of gasoline and increase the yield of C3 toC4 olefins. However, as is known to those skilled in the art, theincrease of the production of propylene and butene is at the expense ofgasoline production.

Accordingly, there remains a need in the art for a process for treatinggasoline that is capable of effectively reducing the sulfur and olefincontent of gasoline while maintaining or even increasing the yield andthe octane number of gasoline.

SUMMARY OF THE INVENTION

It is an object of the present application to provide a process and asystem for treating gasoline that are capable of reducing sulfur andolefin content of gasoline, and at the same time increasing the octanenumber of gasoline while maintaining a high gasoline yield.

In order to achieve the above object, in one aspect, the presentapplication provides a process for treating gasoline, comprising:

1) splitting a gasoline feedstock into a light gasoline fraction and aheavy gasoline fraction;

2) subjecting at least a portion of the resulting light gasolinefraction to etherification to obtain an etherified oil; and

3) contacting the resulting heavy gasoline fraction with a mixedcatalyst and subjecting it to desulfurization and aromatization in thepresence of hydrogen to obtain a heavy gasoline product;

wherein the mixed catalyst comprises an adsorption desulfurizationcatalyst and an aromatization catalyst, and the aromatization catalystis selected from the group consisting of a fresh aromatization catalyst,a passivated aromatization catalyst, an aged aromatization catalyst, orany combination thereof.

In another aspect, the present application provides a process fortreating gasoline, comprising:

1) splitting a gasoline feedstock into a light gasoline fraction and aheavy gasoline fraction;

2) optionally, subjecting at least a portion of the resulting lightgasoline fraction to etherification to obtain an etherified oil; and

3) contacting the resulting heavy gasoline fraction with a mixedcatalyst and subjecting it to desulfurization and aromatization in thepresence of hydrogen to obtain a heavy gasoline product;

wherein the mixed catalyst comprises an adsorption desulfurizationcatalyst and an aromatization catalyst, and at least about 50 wt %,preferably at least about 80 wt %, more preferably at least about 90 wt%, particularly preferably at least about 95 wt %, and most preferablyabout 100 wt % of the aromatization catalyst has undergone a passivationand/or aging treatment.

In still another aspect, the present application provides a system fortreating gasoline, comprising a gasoline feedstock fractionation columnand a desulfurization-aromatization reactor, wherein the gasolinefeedstock fractionation column is provided with a gasoline feedstockinlet, a heavy gasoline fraction outlet, and a light gasoline fractionoutlet; the desulfurization-aromatization reactor is provided with aheavy gasoline fraction inlet, a hydrogen inlet, and adesulfurization-aromatization product outlet; the heavy gasolinefraction outlet of the gasoline feedstock fractionation column is influid communication with the heavy gasoline fraction inlet of thedesulfurization-aromatization reactor,

wherein a gasoline feedstock is introduced into the gasoline feedstockfractionation column through the gasoline feedstock inlet, and subjectedto fractionation therein to obtain a light gasoline fraction and a heavygasoline fraction; the heavy gasoline fraction is introduced into thedesulfurization-aromatization reactor through the heavy gasolinefraction inlet, and subjected to desulfurization and aromatization inthe presence of hydrogen to obtain a desulfurization-aromatizationproduct.

In certain preferred embodiments, the system further comprises a highpressure separator and a mixer, wherein thedesulfurization-aromatization product outlet of thedesulfurization-aromatization reactor is in fluid communication with aninlet of the high pressure separator; an outlet of the high pressureseparator is in fluid communication with an inlet of the mixer; and thelight gasoline fraction outlet of the gasoline feedstock fractionationcolumn is in fluid communication with an inlet of the mixer, wherein thedesulfurization-aromatization product is separated in the high pressureseparator into an olefin-containing tail gas and a heavy gasolineproduct, and the light gasoline fraction is mixed with the heavygasoline product in the mixer to obtain a gasoline product.

In certain preferred embodiments, the system further comprises anetherification unit, wherein the light gasoline fraction outlet of thegasoline feedstock fractionation column is in fluid communication withan inlet of the etherification unit, and the light gasoline fraction issubjected to etherification in the etherification unit to obtain anetherified product.

The present application has at least one of the following advantageouseffects as compared with the prior arts:

1. In the process of the present application, a gasoline feedstock withhigh sulfur and olefin contents is split into a light gasoline fractionand a heavy gasoline fraction, and then the heavy gasoline fraction issubjected to desulfurization and aromatization using an adsorptiondesulfurization catalyst and an aromatization catalyst, so that thesulfur in the gasoline can be reduced and the olefins in the gasolinecan be aromatized at the same time, thereby reducing the olefin contentof the gasoline, and increasing the octane number of the gasoline whilemaintaining a high yield of gasoline.

2. The desulfurization and aromatization of the present application canbe carried out using existing adsorption desulfurization reactors withno need to modify them.

3. The desulfurization and aromatization of the present application arecarried out in one reactor by using two kinds of catalysts, and thus theneed for a separate aromatization reactor and its ancillary system instepwise treatment processes (i.e. desulfurization and thenaromatization or aromatization and then desulfurization) for gasolinecan be avoided. Meanwhile, the problem associated with the modificationof existing processes for producing difunctional catalysts for gasolinedesulfurization and aromatization and the low wear strength of thecatalyst can also be avoided. This provides not only an improvement inthe reaction efficiency, but also a reduction in the investment cost.

4. Preferably, the aromatization catalyst of the present application hasundergone a passivation and/or aging treatment to impart a moderateactivity to the aromatization catalyst, thereby facilitating thearomatization process.

5. In the present application, the light gasoline fraction is preferablysubjected to etherification, which can not only reduce the olefincontent thereof, but also produce a high-octane etherified oil, andincrease the octane number of the gasoline product.

6. The etherification preferably employed in the present application canfurther reduce light components in the gasoline product and thus reducethe vapor pressure of gasoline.

Other features and advantages of the present application will bedescribed in detail in the Detailed Description section below.

BRIEF DESCRIPTION OF THE DRAWINGS

The drawings are provided to help the understanding of the presentapplication, and should be considered as a part of the presentdescription. The present invention will be illustrated with reference tothe drawings and the embodiments described herein below, which shouldnot be considered to be limiting. In the drawings:

FIG. 1 is a schematic illustration of a preferred embodiment of theprocess and system of the present application.

Description of the reference numerals 1 Gasoline feedstock 2 Gasolinefeedstock fractionation column 3 Heavy gasoline fraction 4 Hydrogen 5Desulfurization-aromatization reactor 6 Desulfurization-aromatizationproduct 7 High pressure separator 8 Olefin-containing tail gas 9 Heavygasoline product 10 Light gasoline fraction 11 Pretreatment unit 12Pre-etherification light gasoline 13 Alcohol-containing stream 14Etherification unit 15 Etherification product 16 Etherification productfractionation column 17 Alcohol-containing tail gas 18 Etherified oil 19Mixer 20 Gasoline product 21 Cracking gas separation unit 22 Recyclehydrogen 23 Olefin-containing liquid hydrocarbon

DETAILED DESCRIPTION OF THE INVENTION

Embodiments of the present application will be described in detail belowwith reference to the drawings. It should be understood that theembodiments described herein are merely illustrative and notrestrictive.

Any numerical values (including the endpoints of the numerical ranges)disclosed herein are not limited to the precise value thereof, butshould be understood to cover all values close to said precise value.Moreover, for the numerical ranges disclosed herein, one or more newnumerical ranges can be obtained by combining the endpoints of theranges, combining the endpoints with specific values within the ranges,or combining specific values within the ranges, and such new numericalranges are also considered to be specifically disclosed herein.

The RIPP test methods involved in the present application can be foundin “Petrochemical analysis methods”, edited by Cuiding YANG et al.,Science Press, September 1990, pages 263-268 and 303-304, ISBN:7-03-001894-X.

In a first aspect, the present application provides a process fortreating gasoline, comprising:

1) splitting a gasoline feedstock into a light gasoline fraction and aheavy gasoline fraction;

2) subjecting at least a portion of the resulting light gasolinefraction to etherification to obtain an etherified oil; and

3) contacting the resulting heavy gasoline fraction with a mixedcatalyst and subjecting it to desulfurization and aromatization in thepresence of hydrogen to obtain a heavy gasoline product;

wherein the mixed catalyst comprises an adsorption desulfurizationcatalyst and an aromatization catalyst, and the aromatization catalystis selected from the group consisting of a fresh aromatization catalyst,a passivated aromatization catalyst, an aged aromatization catalyst, orany combination thereof.

In a second aspect, the present application provides a process fortreating gasoline, comprising:

1) splitting a gasoline feedstock into a light gasoline fraction and aheavy gasoline fraction;

2) optionally, subjecting at least a portion of the resulting lightgasoline fraction to etherification to obtain an etherified oil; and

3) contacting the resulting heavy gasoline fraction with a mixedcatalyst and subjecting it to desulfurization and aromatization in thepresence of hydrogen to obtain a heavy gasoline product;

wherein the mixed catalyst comprises an adsorption desulfurizationcatalyst and an aromatization catalyst, and at least about 50 wt %,preferably at least about 80 wt %, more preferably at least about 90 wt%, particularly preferably at least about 95 wt %, and most preferablyabout 100 wt % of the aromatization catalyst has undergone a passivationand/or aging treatment.

In certain preferred embodiments, the process for treating gasolinefurther comprises: 4) mixing at least a portion of the light gasolinefraction and/or at least a portion of the etherified oil with at least aportion of the heavy gasoline product to provide a gasoline product.

As used herein, the term “desulfurization and aromatization” refers to aprocess in which a gasoline feedstock is subjected to desulfurizationand the conversion of olefins to aromatic hydrocarbons by the combinedaction of an adsorption desulfurization catalyst and an aromatizationcatalyst in the presence of hydrogen, which may be accompanied by acracking reaction. In certain preferred embodiments, the desulfurizationand aromatization are carried out under conditions including: a reactiontemperature within a range from about 350 to about 500° C., preferablyfrom about 380 to about 420° C.; and a weight hourly space velocitywithin a range from about 2 h⁻¹ to about 50 h⁻¹, preferably from about 5h⁻¹ to about 20 h⁻¹; a reaction pressure within a range from about 0.5MPa to about 3.0 MPa, preferably from about 1.5 MPa to about 2.5 MPa;and a volume ratio of hydrogen to the heavy gasoline fraction (understandard conditions (STP) 0° C. (273 K), 1.01×10⁵ Pa) within a rangefrom about 1 to about 500, preferably from about 50 to about 200.

The adsorption desulfurization catalyst used in the present applicationis not particularly limited, and may be any catalyst known to thoseskilled in the art that is suitable for used in the adsorptiondesulfurization of gasoline. In some preferred embodiments, theadsorption desulfurization catalyst comprises silica, alumina, zincoxide, and a desulfurization active metal, and the desulfurizationactive metal is at least one selected from the group consisting ofcobalt, nickel, copper, iron, manganese, molybdenum, tungsten, silver,tin and vanadium.

In certain preferred embodiments, on the basis of oxides, the zinc oxideis present in an amount ranging from about 10% to about 90% by weight,the silica is present in an amount ranging from about 5% to about 85% byweight, and the alumina is present in an amount ranging from about 5% toabout 30% by weight based on the dry weight of the adsorptiondesulfurization catalyst; and on the elemental basis, thedesulfurization active metal is present in the adsorptiondesulfurization catalyst in an amount ranging from about 5% to about 30%by weight based on the dry weight of the adsorption desulfurizationcatalyst.

In a preferred embodiment, the adsorption desulfurization catalyst mayfurther comprise about 1% to about 10% by weight of a coke-likematerial. Industrial practice shows that the carbon content on theadsorption desulfurization catalyst has an influence on thedesulfurization efficiency of the adsorption desulfurization catalystand the loss of the octane number of gasoline. With the increase ofcarbon content of the adsorption desulfurization catalyst, thedesulfurization efficiency of the adsorption desulfurization catalyst isgradually decreased, and the loss of the octane number of gasoline isgradually reduced accordingly. Likewise, it is highly preferable thatthe adsorption desulfurization catalyst has a certain sulfur content.The practice shows that the sulfur content of a spent adsorptiondesulfurization catalyst is in a range from about 9% to about 10% byweight, the sulfur content of a regenerated adsorption desulfurizationcatalyst is in a range from about 5% to about 6% by weight, and it ismost preferable that the difference in sulfur content between the spentadsorption desulfurization catalyst and the regenerated adsorptiondesulfurization catalyst is about 4% by weight.

As used herein, the term “aromatization catalyst” refers to a catalystcapable of converting a hydrocarbon such as an olefin or the like in agasoline feedstock into an aromatic hydrocarbon, which generallycomprises a molecular sieve, and preferably comprises a molecular sieve,a support, and a metal. In certain preferred embodiments, on dry basis,the aromatization catalyst comprises about 10% to about 30% by weight ofa molecular sieve, about 0% to about 20% by weight of an aromatizationactive metal oxide and about 50% to about 90% by weight of a support,based on the total weight of the aromatization catalyst.

In certain further preferred embodiments, the molecular sieve comprisesa Y molecular sieve and/or an MFI structural molecular sieve, preferablya five-membered high silica molecular sieve, which may be of thehydrogen type or may be modified by a rare earth metal and/orphosphorus, preferably having a silica-alumina ratio of greater than100, more preferably greater than 150.

In certain further preferred embodiments, the aromatization active metalmay show some desulfurization or hydrocarbon conversion capability, andmay, for example, be at least one selected from the group consisting ofmetal elements of Group IVB, metal elements of Group VB, metal elementsof Group VIB, metal elements of Group VIII, metal elements of Group IB,metal elements of Group IIB, and metal elements of Group IIIA. Incertain still further preferred embodiments, the metal element of GroupIVB is Zr or/and Ti, the metal element of Group VB is V, the metalelement of Group VIB is Mo or/and W, the metal element of Group VIII isone or more selected from the group consisting of Fe, Co, and Ni, themetal element of Group IB is Cu, the metal element of Group IIB is Zn,and the metal element of Group IIIA is Ga. In some particularlypreferred embodiments, the aromatization active metal is at least oneselected from the group consisting of Fe, Zn and Ga, and its content ispreferably within a range from about 0.5% to about 5% by weight.

In certain further preferred embodiments, the support comprises silicaand/or alumina.

In certain preferred embodiments, the aromatization catalyst typicallyhas a particle size within a range from 20 to 120 microns, which iscomparable to the particle size of the adsorption desulfurizationcatalyst. Preferably, in the present application, the adsorptiondesulfurization catalyst and the aromatization catalyst are separatelyformed (for example, by spray drying) and then mixed before use.

The ratio of the adsorption desulfurization catalyst to thearomatization catalyst in the mixed catalyst of the present applicationmay vary depending on the olefin and sulfur content of the gasolinefeedstock. In certain preferred embodiments, the percentage by weight ofthe aromatization catalyst in the mixed catalyst is within a range fromabout 1% to about 30% by weight, preferably from about 3% to about 15%by weight.

In certain preferred embodiments, the aromatization catalyst of thepresent application can be prepared in accordance with the followingsteps: mixing the starting material for preparing the aromatizationcatalyst with water to make a slurry, and then subjecting the slurry tospray-drying and calcination; wherein the starting material comprisesabout 15% to about 60% by weight of a natural mineral, about 10% toabout 30% by weight of a precursor of an inorganic oxide binder, andabout 20% to about 80% by weight of a MFI structural molecular sievecontaining phosphorus and supported metal, based on the dry weight ofthe starting material.

In a further preferred embodiment, the starting material comprises about20% to about 55% by weight of the natural mineral, about 12% to about28% by weight of the precursor of the inorganic oxide binder and about35% to about 70% by weight of the MFI structural molecular sievecontaining phosphorus and supported metal, based on the dry weight ofthe starting material.

As used herein, the term “natural mineral” refers to a natural elementor compound formed under the combined action of various substances inthe earth's crust (called geological action), which has a characteristicand relatively fixed chemical composition that can be expressed by achemical formula. For example, it may comprise at least one selectedfrom the group consisting of kaolin clay, halloysite, montmorillonite,diatomaceous earth, attapulgite, sepiolite, indianite, hydrotalcite,bentonite, and rectorite.

As used herein, the term “inorganic oxide binder” refers to an inorganicoxide that acts as a binder in the catalyst, and may, for example,comprise at least one selected from the group consisting of silica,alumina, zirconia, titania and amorphous silica-alumina.

As used herein, the term “precursor of an inorganic oxide binder” refersto a starting material for preparing a catalytic cracking catalyst,which is generally used for producing an inorganic oxide binder in thecatalytic cracking catalyst, and may, for example, comprise at least oneselected from the group consisting of silica sol, alumina sol, peptizedpseudo-boehmite, silica-alumina sol, and phosphorus-containing aluminasol.

As used herein, the term “supported metal” refers to a metal supportedon a molecular sieve by a loading method, excluding aluminum and alkalimetals such as sodium or potassium. The supported metal used in thepresent application is not particularly limited and may be zinc, galliumand/or iron, and may also include other metals.

In certain further preferred embodiments, the supported metal is zincand/or gallium, and the natural mineral comprises at least one selectedfrom the group consisting of kaolin clay, halloysite, montmorillonite,diatomaceous earth, attapulgite, sepiolite, indianite, hydrotalcite,bentonite, and rectorite, and the inorganic oxide binder comprises atleast one selected from the group consisting of silica, alumina,zirconia, titania, and amorphous silica-alumina.

In certain still further preferred embodiments, the MFI structuralmolecular sieve is at least one selected from the group consisting ofZSM-5, ZSM-8, and ZSM-11.

In certain preferred embodiments, the MFI structural molecular sieve inthe aromatization catalyst has a n(SiO₂)/n(Al₂O₃) ratio of greater thanabout 100; the molecular sieve has a phosphorus content, on the basis ofP₂O₅, within a range from about 0.1% to about 5% by weight, based on thedry weight of the molecular sieve; the molecular sieve has asupported-metal content, on the basis of oxides, within a range fromabout 0.5% to about 5% by weight, based on the dry weight of themolecular sieve; the A1 distribution parameter D(A1) of the molecularsieve satisfies: 0.6≤D(A1)≤0.85, wherein D(A1)=A1(S)/A1(C), and A1(S)denotes the aluminum content in any region of greater than 100 squarenanometers within an inward distance H from the edge of the crystal faceof the molecular sieve grain determined by the TEM-EDS method (where TEMmeans transmission electron microscope, EDS means X-ray energy spectrum,and TEM-EDS means transmission electron microscope with X-ray energyspectrum); A1(C) denotes the aluminum content in any region of greaterthan 100 square nanometers within an outward distance H from thegeometric center of the crystal face of the molecular sieve graindetermined by the TEM-EDS method, wherein H denotes 10% of the distancefrom a certain point at the edge of the crystal face to the geometriccenter of the crystal face; the supported-metal distribution parameterD(M) of the molecular sieve satisfies: 2≤D(M)≤10, where D(M)=M(S)/M(C),and M(S) denotes the supported-metal content in any region of greaterthan 100 square nanometers within an inward distance H from the edge ofthe crystal face of the molecular sieve grain determined by the TEM-EDSmethod, M(C) denotes the supported-metal content in any region ofgreater than 100 square nanometers within an outward distance H from thegeometric center of the crystal face of the molecular sieve graindetermined by the TEM-EDS method; the molecular sieve has a mesoporevolume percentage within a range from about 40% to about 80% relative tothe total pore volume thereof, with the volume percentage of mesoporeshaving a pore diameter within a range from about 2 nm to about 20 nmrelative to the total mesopore volume being preferably greater thanabout 90%; and the molecular sieve has a percentage of strong acidcontent relative to the total acid content within a range from about 60%to about 80%, with a ratio of the Bronsted acid (B acid) content to theLewis acid (L acid) content being within a range from about 15 to about80.

In certain further preferred embodiments, the MFI structural molecularsieve has a n(SiO₂)/n(Al₂O₃) ratio of greater than about 120; themolecular sieve has a phosphorus content, on the basis of P₂O₅, within arange from about 0.2% to about 4% by weight, based on the dry weight ofthe molecular sieve; the molecular sieve has a supported-metal content,on the basis of oxides, within a range from about 0.5% to about 3% byweight, based on the dry weight of the molecular sieve; the A1distribution parameter D(A1) of the molecular sieve satisfies:0.65≤D(A1)≤0.8; the supported-metal distribution parameter D(M) of themolecular sieve satisfies: 3≤D(M)≤6; the molecular sieve has a mesoporevolume percentage within a range from about 50% to about 70% relative tothe total pore volume thereof, with the volume percentage of mesoporeshaving a pore diameter within a range from about 2 nm to about 20 nmrelative to the total mesopore volume being greater than about 92%; andthe molecular sieve has a percentage of strong acid content relative tothe total acid content within a range from about 65% to about 75%, withthe ratio of the B acid content to the L acid content being within arange from about 20 to about 50.

The TEM-EDS method used in the present application for determining thealuminum content and the supported-metal content of the molecular sieveis well known to those skilled in the art, wherein the determination ofthe geometric center is also well known to those skilled in the art andcan be calculated according to a formula, which will not be describedherein in detail. The geometric center of a symmetrical figure isgenerally the intersection of the lines connecting the opposite verticesthereof. For example, the geometric center of the hexagonal crystal faceof a conventional hexagonal ZSM-5 molecular sieve is at the intersectionof the three lines connecting the opposite vertices thereof, where thecrystal face is one face of a regular grain, and the inward and outwarddirections refer to the inward and outward directions on the crystalface.

According to the present application, the mesopore volume percentage ofthe molecular sieve relative to the total pore volume thereof isdetermined by the nitrogen adsorption BET specific surface areameasuring method, wherein the mesopore volume refers to the volume ofpores having a pore diameter greater than about 2 nm and less than about100 nm; the percentage of strong acid content to the total acid contentof the molecular sieve is determined by the NH₃-TPD method, wherein theacid center of the strong acid is specified as the acid center having acorresponding NH₃ desorption temperature of greater than 300° C.; theratio of the B acid content to the L acid content is determined by thepyridine adsorption infrared acidity measuring method.

In certain preferred embodiments, the MFI structural molecular sievecontaining phosphorus and supported metal can be prepared in accordancewith the following steps:

a. subjecting a crystallized MFI structural molecular sieve slurry tofiltration and washing, to obtain a water-washed molecular sieve,wherein the water-washed molecular sieve has a sodium content, on thebasis of sodium oxide, of less than 3% by weight, based on the total dryweight of the water-washed molecular sieve;

b. subjecting the water-washed molecular sieve obtained in step a todesiliconization in an alkaline solution, and then to filtration andwashing, to obtain a desiliconized molecular sieve;

c. subjecting the desiliconized molecular sieve obtained in step b toammonium ion-exchange to obtain an ammonium ion-exchanged molecularsieve, wherein the ammonium ion-exchanged molecular sieve has a sodiumcontent, on the basis of sodium oxide, of less than 0.2% by weight,based on the total dry weight of the ammonium ion-exchanged molecularsieve;

d. subjecting the ammonium ion-exchanged molecular sieve obtained instep c to dealumination in a composite acid dealuminant solutionconsisting of a fluorosilicic acid, an organic acid and an inorganicacid, and then to filtration and washing, to obtain a dealuminatedmolecular sieve;

e. subjecting the dealuminated molecular sieve obtained in the step d tophosphorus modification and loading of the supported metal, to obtain amodified molecular sieve; and

f. subjecting the modified molecular sieve obtained in the step e tohydrothermal calcination to obtain the MFI structural molecular sievecontaining phosphorus and supported metal.

The “crystallized MFI structural molecular sieve slurry” used in thestep a of the present application can be obtained by methods well knownto those skilled in the art, and will not be described herein in detail.In addition, the MFI structural molecular sieve is also well known tothose skilled in the art, and may be obtained by amine-freecrystallization, or may be a molecular sieve prepared by a templatingmethod. The molecular sieve obtained by amine-free crystallization doesnot need to be calcined, while the molecular sieve prepared by thetemplating method needs to be calcined in air after drying, and theZSM-5 molecular sieve normally has a silica-alumina ratio of less than100.

The desiliconization performed using an alkaline solution in the step bof the present application is well known to those skilled in the art.For example, the alkaline solution used in the step b may be selectedfrom the group consisting of sodium hydroxide solution and/or potassiumhydroxide solution, preferably sodium hydroxide solution. Thedesiliconization conditions may include: a weight ratio on dry basis ofthe molecular sieve to the alkali in the alkaline solution within arange of about 1:(0.1-1), preferably about 1:(0.15-0.4); adesiliconization temperature within a range from room temperature toabout 100° C., preferably from about 50 to about 85° C., adesiliconization time within a range from about 15 minutes to about 8hours, preferably from about 30 minutes to about 4 hours.

The ammonium ion-exchange carried out in the step c of the presentapplication is well known to those skilled in the art. For example, instep c, the alkali-treated desiliconized molecular sieve can besubjected to ion exchange at a temperature within a range from roomtemperature to about 100° C. for about 0.5 to about 2 hours with aweight ratio of the molecular sieve:ammonium salt:H₂O within a range ofabout 1:(0.1-1):(5-10), and then to filtration, so as to provide a Na₂Ocontent of the zeolite of less than about 0.2% by weight. The ammoniumsalt may be any commonly used inorganic ammonium salt, for example, atleast one selected from the group consisting of ammonium chloride,ammonium sulfate, and ammonium nitrate.

The “dealumination” treatment involved in the step d of the presentapplication is known per se to those skilled in the art, but it has notbeen reported to use a combination of an inorganic acid, an organic acidand a fluorosilicic acid in the dealumination as in the step d of thepresent application. The dealumination may be carried out in one or morestages, in which the organic acid may be firstly mixed with the ammoniumion-exchanged molecular sieve, and then the fluorosilicic acid and theinorganic acid may be mixed with the ammonium ion-exchanged molecularsieve, that is, the organic acid may be firstly added into the ammoniumion-exchanged molecular sieve, and the fluorosilicic acid and theinorganic acid may then be slowly added in a co-current manner, oralternatively the fluorosilicic acid and the inorganic acid may be addedsuccessively, preferably the fluorosilicic acid and the inorganic acidare slowly added in a co-current manner. The dealumination can becarried out under the following conditions: a weight ratio on dry basisof the molecular sieve:fluorosilicic acid:organic acid:inorganic acidwithin a range of about 1:(0.02-0.5):(0.05-0.5):(0.05-0.5), preferablyabout 1:(0.05-0.3):(0.1-0.3):(0.1-0.3); a treatment temperature within arange from about 25 to about 100° C., and a treatment time within arange from about 0.5 to about 6 hours.

It has been proved via experimentation that, by using the composite acidsystem in the dealumination of the present application, thesilica-alumina ratio of the molecular sieve can be effectively improved,the aluminum distribution can be adjusted, and the acid distribution canbe improved while maintaining the crystal structure of the molecularsieve and the integrity of its pore structure of mesopores, under thesynergistic action of the three acids.

The organic acid and the inorganic acid used in the step d of thepresent application may be those conventionally used in the art. Forexample, the organic acid may be at least one selected from the groupconsisting of ethylenediamine tetraacetic acid, oxalic acid, citricacid, and sulfosalicylic acid, preferably oxalic acid; and the inorganicacid may be at least one selected from the group consisting ofhydrochloric acid, sulfuric acid and nitric acid, preferablyhydrochloric acid.

The washing carried out in the step d of the present application is wellknown to those skilled in the art, and may be carried out, for example,by rinsing the filtered molecular sieve with about 5-10 times of waterat about 30-60° C.

The phosphorus modification and the loading of the supported metalcarried out in the step e of the present application are well known tothose skilled in the art. For example, the phosphorus modification inthe step e may comprise the step of subjecting the molecular sieve toimpregnation and/or ion exchange with at least one phosphorus-containingcompound selected from the group consisting of phosphoric acid, ammoniumhydrogen phosphate, ammonium dihydrogen phosphate and ammoniumphosphate; and the loading of the supported metal in the step e maycomprise the steps of: dissolving a soluble salt containing at least onesupported metal selected from the group consisting of zinc and galliumin deionized water, adjusting the pH with ammonia water to precipitatethe supported metal in the form of hydroxide, and then mixing theresulting precipitate uniformly with the molecular sieve.

The hydrothermal calcination of the molecular sieve carried out in thestep f of the present application is well known to those skilled in theart. For example, the hydrothermal calcination in the step f can becarried out under the following conditions: a calcination atmosphere ofsteam, a calcination temperature within a range from about 400 to about800° C. and a calcination time within a range from about 0.5 to about 8hours.

In certain preferred embodiments, the inventors of the presentapplication have surprisingly found that a better effect can be obtainedby using an aromatization catalyst having a micro-activity within arange from about 20 to about 55, which can be determined according tothe test method of RIPP 92-90 in catalytic cracking field fordetermining the micro-activity of equilibrium catalysts, for which thedetails can be referred to the working examples. Generally, commerciallyavailable or self-made qualified fresh aromatization catalysts normallyhave a micro-activity above 60, and thus show a higher activity and astronger cracking performance. Therefore, prior to use in thedesulfurization and aromatization, such fresh aromatization catalystsare preferably subjected to a pre-treatment to reduce the acid contentand increase the acid strength, thereby facilitating the reduction ofthe hydrogen transfer reaction.

In certain preferred embodiments, the aromatization catalyst has beensubjected to passivation prior to use in the desulfurization andaromatization. Preferably, the passivation comprises the step ofcontacting the aromatization catalyst, such as a fresh aromatizationcatalyst, with a compound containing carbon, sulfur and/or nitrogen toconduct a passivation reaction.

In certain further preferred embodiments, the passivated aromatizationcatalyst comprises about 0.1% to about 5.0% by weight of passivatedspecies, wherein the passivated species comprises at least one elementselected from the group consisting of carbon, sulfur, and nitrogen.

In certain preferred embodiments, the passivation can be carried out ina reactor located outside of the desulfurization-aromatization reactor,or in the pre-lift segment of a fluidized reactor used as thedesulfurization-aromatization reactor. The compound containing carbon,sulfur and/or nitrogen used for the passivation may be gasoline,hydrogen sulfide, carbon disulfide, ammonia, anilines, pyridines orquinolines, etc. The gasoline may be the gasoline feedstock used, orother gasoline from the outside, such as catalytic cracking gasoline,steam cracking gasoline or other olefin-containing gasoline.

In certain preferred embodiments, the aromatization catalyst issubjected to an aging treatment prior to use in the desulfurization andaromatization. As used herein, the term “aging” refers to a process inwhich the aromatization catalyst, such as a fresh aromatizationcatalyst, is subjected to a treatment at elevated temperature in thepresence of steam to reduce its activity. In certain further preferredembodiments, the aging treatment is carried out under the followingconditions: a temperature within a range from about 500 to about 800°C., preferably from about 600 to about 800° C., more preferably fromabout 700 to about 800° C.; an ageing time within a range from about 1to about 360 hours, preferably from about 2 to about 48 hours, morepreferably from about 4 to about 24 hours; and an aging atmospherecontaining steam, preferably an atmosphere comprising about 100% steam.

In certain preferred embodiments of the aging treatment, the fresharomatization catalyst is contacted with steam or an aging mediumcontaining steam, and aged in a hydrothermal environment at atemperature within a range from about 500° C. to about 800° C. for about1 hour to about 360 hours, to obtain an aged aromatization catalyst. Incertain further preferred embodiments, the aging medium may compriseair, dry gas, regenerated flue gas, gas obtained after the combustion ofa dry gas in air, gas obtained after the combustion of burning oil inair, or other gases such as nitrogen. Preferably, the weight fraction ofsteam in the aging medium containing steam is within a range from about0.2 to about 0.9, more preferably from about 0.40 to about 0.60.Preferably, the regenerated flue gas may come from the catalystregeneration unit of the present application or may come from aregeneration unit of other processes.

In certain preferred embodiments, the aging treatment is carried out inan aging reactor, preferably a dense phase fluidized bed. In certainfurther preferred embodiments, the aging treatment comprises the step ofsubjecting the fresh aromatization catalyst to aging at 800° C. underthe condition of 100% steam for a time period within a range from 4 h to17 h.

In certain preferred embodiments, at least about 50 wt %, preferably atleast about 80 wt %, more preferably at least about 90 wt %,particularly preferably at least about 95 wt %, and most preferablyabout 100 wt % of the aromatization catalyst has undergone a passivationand/or aging treatment.

The desulfurization and aromatization of the present application arepreferably carried out in a fluidized reactor to facilitate a rapidregeneration of the aromatization catalyst. In certain preferredembodiments, the fluidized reactor is selected from the group consistingof fluidized bed reactors, riser reactors, downer reactors, compositereactors composed of a riser reactor and a fluidized bed reactor,composite reactors composed of a riser reactor and a downer reactor,composite reactors composed of two or more riser reactors, compositereactors composed of two or more fluidized bed reactors, and compositereactors composed of two or more downer reactors, preferably a riserreactor, a fluidized bed reactor or a combination thereof. Preferably,each of the above reactors may be divided into two or more reactionzones. In certain preferred embodiments, the fluidized bed reactor isone or more selected from the group consisting of fixed fluidized bed,particulately fluidized bed, bubbling bed, turbulent bed, fast bed,transport bed, and dense phase fluidized bed reactors. The riser reactoris one or more selected from the group consisting of equal-diameterriser reactors, equal-linear-speed riser reactors, and variousunequal-diameter riser reactors. In a particularly preferred embodiment,the fluidized reactor is a dense phase fluidized reactor.

The gasoline feedstock used in the present application may be anyconventional gasoline feedstock commonly used in the art. In certainpreferred embodiments, the gasoline feedstock may be at least oneselected from the group consisting of catalytic cracking gasoline, deepcatalytic cracking gasoline, coker gasoline, thermal cracking gasoline,and straight-run gasoline, or a fraction thereof. In certain preferredembodiments, the gasoline feedstock is a gasoline having a high olefinand sulfur content, of which the olefin volume fraction is generallygreater than about 20% by volume, preferably greater than about 30% byvolume, more preferably greater than about 40% by volume, and even morepreferably greater than about 50% by volume; and the sulfur content isgenerally about 10 μg/g or above, preferably greater than about 50 μg/g,more preferably greater than about 100 μg/g, further preferably greaterthan about 500 μg/g, still more preferably greater than about 1000 μg/g.The organic sulfide in the gasoline feedstock is not particularlylimited, and may be, for example, mercaptan, thioether, thiophene,alkylthiophene, benzothiophene, and/or methylbenzothiophene.

The split point between the light gasoline fraction and the heavygasoline fraction adopted in the present application may be varied asneeded. In certain preferred embodiments, the split point between thelight gasoline fraction and the heavy gasoline fraction is within arange from 60 to 80° C., more preferably from about 65 to about 70° C.In certain further preferred embodiments, the gasoline feedstock issplit in the fractionation column in accordance with the distillationrange from low to high. More preferably, the fractionation column forsplitting the gasoline is operated under the following conditions: anoverhead temperature within a range from about 60 to about 80° C., abottom temperature within a range from about 120 to about 160° C. and anoperating pressure within a range from about 0.05 to about 0.3 MPa.

As used herein, the term “etherification” refers to a process in which alower hydrocarbon (e.g., isopentene and cyclopentene) below C5 in thelight gasoline fraction is subjected to an etherification reaction withan alcohol to produce a high-octane etherified oil. In certain preferredembodiments, the etherification comprises the step of contacting thelight gasoline fraction with an alcohol to subject the olefin in thelight gasoline fraction to an etherification reaction with the alcoholin the presence of an etherification catalyst, to obtain the etherifiedoil, wherein the etherification is carried out under the followingconditions: a temperature within a range from about 20 to about 200° C.,a pressure within a range from about 0.1 to about 5 MPa, a weight hourlyspace velocity within a range from about 0.1 to about 20 h⁻¹, and amolar ratio of the alcohol to the light gasoline fraction within a rangeof about 1:(0.1-100). In certain further preferred embodiments, theetherification catalyst comprises at least one selected from the groupconsisting of resins, molecular sieves, and heteropolyacids. In certainstill further preferred embodiments, the alcohol is at least oneselected from the group consisting of methanol, ethanol, and propanol.

In certain preferred embodiments of the etherification, a stronglyacidic cation-exchange resin catalyst is charged in a one-stageetherification and/or two-stage etherification fixed bed reactor, and alight gasoline fraction that has undergone a pre-treatment such asdesulfurization and removal of dienes is passed into the etherificationfixed bed reactor to conduct an etherification reaction under thefollowing conditions: a reaction temperature within a range from about50 to about 90° C., a liquid hourly space velocity within a range fromabout 1.0 to about 3.0 h⁻¹, and a molar ratio of methanol to activeolefins in the light gasoline fraction within a range from about 1 toabout 2, the etherified product is sent to a rectification column forseparation, an etherified oil is obtained at the bottom of the column,and unreacted light hydrocarbons and methanol are recycled. As usedherein, the term “active olefin” refers to an olefin having a doublebond at a tertiary carbon atom.

In certain further preferred embodiments, the etherification is carriedout under the following conditions: a reaction temperature comprising aninlet temperature within a range from about 55 to about 60° C. and anoutlet temperature of less than about 90° C., a space velocity within arange from about 1 to about 2 h⁻¹, and a molar ratio of methanol toactive olefins in the light gasoline fraction within a range from about1.2 to about 1.4. In some embodiments, the olefin content in one-stageetherification is relatively high, and a mixed-phase bed reactor issuitable for use therein; while the olefin content in two-stageetherification is relatively low, and an adiabatic fixed-bed reactor issuitable for use therein. In certain preferred embodiments, anisomerization unit can also be employed in the light gasolineetherification process. Light gasoline etherification has manyadvantages, such as reducing the olefin content of gasoline, increasingthe octane number, lowering the vapor pressure, increasing the addedvalue and enhancing the blending efficiency. The etherified oil can beused as a blending component for adjusting the octane number ofgasoline, or can be mixed with the heavy gasoline fraction to provide afull-range gasoline product.

In certain preferred embodiments, the light gasoline fraction has beensubjected to a pre-treatment prior to the etherification to removeimpurities such as sulfur compounds and/or dienes, thereby prolongingthe service life of the etherification catalyst. In certain furtherpreferred embodiments, the pretreatment is at least one selected fromthe group consisting of alkaline liquid extraction, mercaptanconversion, and selective hydrotreatment. In certain still furtherpreferred embodiments, the alkaline liquid extraction is used to removemercaptan from the light gasoline fraction using an alkaline solution byextracting the mercaptan into the alkaline solution; the mercaptanconversion is used to remove small-molecule mercaptan by converting itinto other sulfides, which can be carried out by a conventionalalkali-free deodorization process, a pre-hydrogenation process, etc.,wherein the catalyst and the cocatalyst used can be catalysts commonlyused in the art. The selective hydrotreatment is well known to thoseskilled in the art, and is used to remove dienes from gasoline and allowthe isomerization of 3-methyl-1-butene to 2-methyl-1-butene.

In a third aspect, the present application provides a system fortreating gasoline, comprising a gasoline feedstock fractionation columnand a desulfurization-aromatization reactor, wherein the gasolinefeedstock fractionation column is provided with a gasoline feedstockinlet, a heavy gasoline fraction outlet, and a light gasoline fractionoutlet; the desulfurization-aromatization reactor is provided with aheavy gasoline fraction inlet, a hydrogen inlet, and adesulfurization-aromatization product outlet; the heavy gasolinefraction outlet of the gasoline feedstock fractionation column is influid communication with the heavy gasoline fraction inlet of thedesulfurization-aromatization reactor,

wherein a gasoline feedstock is introduced into the gasoline feedstockfractionation column through the gasoline feedstock inlet, and subjectedto fractionation therein to obtain a light gasoline fraction and a heavygasoline fraction; the heavy gasoline fraction is introduced into thedesulfurization-aromatization reactor through the heavy gasolinefraction inlet, and subjected to desulfurization and aromatization inthe presence of hydrogen to obtain a desulfurization-aromatizationproduct.

In certain preferred embodiments, the system further comprises a highpressure separator and a mixer, the high pressure separator beingprovided with a desulfurization-aromatization product inlet, anolefin-containing tail gas outlet, and a heavy gasoline product outlet,wherein the desulfurization-aromatization product outlet of thedesulfurization-aromatization reactor is in fluid communication with thedesulfurization-aromatization product inlet of the high pressureseparator; the heavy gasoline product outlet of the high pressureseparator is in fluid communication with an inlet of the mixer and thelight gasoline fraction outlet of the gasoline feedstock fractionationcolumn is in fluid communication with an inlet of the mixer, wherein thedesulfurization-aromatization product is separated in the high pressureseparator to produce an olefin-containing tail gas and a heavy gasolineproduct, and the light gasoline fraction is mixed with the heavygasoline product in the mixer to obtain a gasoline product.

In certain preferred embodiments, the system further comprises anetherification unit, wherein the light gasoline fraction outlet of thegasoline feedstock fractionation column is in fluid communication withan inlet of the etherification unit, and the light gasoline fraction issubjected to etherification in the etherification unit to obtain anetherified product.

In certain further preferred embodiments, the system further comprises apretreatment unit, wherein the light gasoline fraction outlet of thegasoline feedstock fractionation column is in fluid communication withthe inlet of the etherification unit via the pretreatment unit.

In certain further preferred embodiments, the system further comprises acracking gas separation unit, the olefin-containing tail gas outlet ofthe high pressure separator being in fluid communication with an inletof the cracking gas separation unit, wherein the olefin-containing tailgas is separated in the cracking gas separation unit to obtain a recyclehydrogen and an olefin-containing liquid hydrocarbon, and theolefin-containing liquid hydrocarbon is sent to the etherification unitfor etherification.

In certain further preferred embodiments, the system further comprisesan etherification product fractionation column, wherein theetherification product fractionation column is provided with anetherification product inlet, an alcohol-containing tail gas outlet, andan etherified oil outlet; an outlet of the etherification unit is influid communication with the etherification product inlet of theetherification product fractionation column, and the etherified oiloutlet of the etherification product fractionation column is in fluidcommunication with an inlet of the mixer;

wherein the etherification product is introduced into the etherificationproduct fractionation column through the etherification product inlet,and subjected to fractionation therein to obtain an alcohol-containingtail gas and an etherified oil, and the light gasoline fraction and/orthe etherified oil is mixed with the heavy gasoline product in the mixerto obtain a gasoline product.

In certain preferred embodiments, the heavy gasoline fraction inlet andthe hydrogen inlet of the desulfurization-aromatization reactor are thesame inlet.

A preferred embodiment of the process and system of the presentapplication is described herein below with reference to the drawings,with no limitation to the present application.

As shown in FIG. 1, in a preferred embodiment, the gasoline treatingsystem of the present application comprises a gasoline feedstockfractionation column 2, a desulfurization-aromatization reactor 5, ahigh pressure separator 7, a pretreatment unit 11, an etherificationunit 14, an etherification product fractionation column 16, a mixer 19and a cracking gas separation unit 21, the gasoline feedstockfractionation column 2 being provided with a gasoline feedstock inlet, aheavy gasoline fraction outlet, and a light gasoline fraction outlet,the desulfurization-aromatization reactor 5 being provided with a heavygasoline fraction inlet, a hydrogen inlet, and adesulfurization-aromatization product outlet, the high pressureseparator 7 being provided with a desulfurization-aromatization productinlet, an olefin-containing tail gas outlet, and a heavy gasolineproduct outlet, the etherification product fractionation column 16 beingprovided with an etherification product inlet, an alcohol-containingtail gas outlet, and an etherified oil outlet; wherein the lightgasoline fraction outlet of the gasoline feedstock fractionation column2 is in fluid communication with the etherification product inlet of theetherification product fractionation column 16 through the pretreatmentunit 11 and the etherification unit 14 successively, the etherified oiloutlet of the etherification product fractionation column 16 is in fluidcommunication with an inlet of the mixer 19; the heavy gasoline fractionoutlet of the gasoline feedstock fractionation column 2 is in fluidcommunication with the heavy gasoline fraction inlet of thedesulfurization-aromatization reactor 5, thedesulfurization-aromatization product outlet of thedesulfurization-aromatization reactor 5 is in fluid communication withthe desulfurization-aromatization product inlet of the high pressureseparator 7, the heavy gasoline product outlet of the high pressureseparator 7 is in fluid communication with an inlet of the mixer 19, andthe olefin-containing tail gas outlet of the high pressure separator 7is in fluid communication with an inlet of the cracking gas separationunit 21.

In the preferred embodiment illustrated in FIG. 1, the process of thepresent application comprises the step of feeding a gasoline feedstock 1with a high olefin and sulfur content to a gasoline feedstockfractionation column 2 for fractional distillation, to obtain a lightgasoline fraction 10 and a heavy gasoline fraction 3. The light gasolinefraction 10 is introduced into the pretreatment unit 11 and subjected toa pretreatment such as mercaptan removal to obtain a pre-etherificationlight gasoline 12, which is mixed with the alcohol-containing stream 13and reacted in the etherification unit 14, the resulting etherifiedproduct 15 is fractionated in the etherification product fractionationcolumn 16 to obtain an etherified oil 18 and an alcohol-containing tailgas 17. The heavy gasoline fraction 3 is mixed with a hydrogen gas 4 andthen introduced into the desulfurization-aromatization reactor 5, and iscontacted with an adsorption desulfurization catalyst and anaromatization catalyst for adsorption desulfurization and aromatization,and the desulfurization-aromatization product 6 is introduced into thehigh pressure separator 7 for separation to obtain an olefin-containingtail gas 8 and a heavy gasoline product 9. The olefin-containing tailgas 8 is separated in the cracking gas separation unit 21 to obtain arecycle hydrogen 22 and an olefin-containing liquid hydrocarbon 23,which is combined into the pre-etherification light gasoline 12 from thepretreatment unit 11. The heavy gasoline product 9 is combined with theetherified oil 18 obtained after etherification in the mixer 19 toprovide a high-octane clean gasoline product 20.

EXAMPLES

The present application will be further illustrated with reference tothe following working examples, without however limiting the presentapplication.

Methods for Measurement

In the present application, the degree of crystallinity is determinedaccording to the standard method of ASTM D5758-2001 (2011) el.

In the present application, the silica-alumina ratio, n(SiO₂)/n(Al₂O₃),is calculated based on the contents of silica and alumina, and thecontents of silica and alumina are determined according to the standardmethod of GB/T 30905-2014.

In the present application, the phosphorus content is determinedaccording to the standard method of GB/T 30905-2014, the content of thesupported metal is determined according to the standard method of GB/T30905-2014, and the sodium content is determined according to thestandard method of GB/T 30905-2014.

For the TEM-EDS measurement method used in the present application, see“Research Technique for Solid Catalysts”, Yongfang XUE, Petrochemicals,29(3), 2000: pages 227-235.

In the present application, the total specific surface area (S_(BET)),the mesopore volume, the total pore volume, and the volume of mesoporeshaving a diameter of 2-20 nm are determined as follows.

The AS-3, AS-6 Static Nitrogen Adsorbers manufactured by QuantachromeInstruments were used for measurement.

Instrument parameters: The sample was placed in a sample treatingsystem, evacuated to 1.33×10⁻² Pa at 300° C., and kept at thetemperature and pressure for 4 h to purify the sample. The adsorptionamount and desorption amount of nitrogen in the purified sample at aliquid nitrogen temperature of −196° C. under different specificpressure P/P₀ conditions were tested, and an N₂ adsorption-desorptionisotherm curve was obtained. Then, the two-parameter BET equation wasused to calculate the total specific surface area, the specific surfacearea of micropores and the specific surface area of mesopores. Theadsorption amount under the specific pressure P/P₀=0.98 was recorded asthe total pore volume of the sample, and the pore size distribution ofmesopores was calculated according to the BJH equation and the mesoporevolume (2-100 nm) and the volume of mesopores having a diameter of 2-20nm were calculated using the integral method.

In the present application, the method for determining the B acidcontent and the L acid content is as follows.

The FTS3000 type Fourier Infrared Spectrometer manufactured by AmericanBIO-RAD company was used for measurement.

Test conditions: The sample was compressed into tablets and placed in anin-situ bath of the infrared spectrometer and sealed, evacuated to 10⁻³Pa at 350° C., and held for 1 h to allow a complete desorption of thegas molecules on the surface of the sample, and then cooled to roomtemperature. Pyridine vapor at a pressure of 2.67 Pa was introduced intothe in-situ bath, equilibrated for 30 min, warmed to 200° C., evacuatedagain to 10⁻³ Pa, held for 30 min, cooled to room temperature, andscanned within the wavenumber range of 1400-1700 cm⁻¹. The infraredspectrum of the pyridine adsorption at 200° C. was recorded. The samplein the infrared absorption cell was moved to a heat treatment zone,heated to 350° C., evacuated to 10⁻³ Pa, held for 30 min, and cooled toroom temperature. The infrared spectrum of the pyridine adsorption at350° C. was recorded. The B acid content and the L acid content can beobtained via automatic integration by the instrument.

In the present application, the method for determining the total acidcontent and the strong acid content is as follows.

The Autochem II2920 Temperature Programming Desorber of MicromeriticsInstrument Corporation, USA, was used for measurement.

Test conditions: 0.2 g of the sample to be tested was weighed into asample tube, placed in a thermal conductivity cell heating device, withHe gas being used as the carrier gas (50 mL/min), heated up to 600° C.at a heating rate of 20° C./min, and purged for 60 min to drive offimpurities adsorbed on the surface of the catalyst. Then, the sample wascooled to 100° C., kept at the temperature for 30 min, switched to aNH₃—He gas mixture (10.02% NH₃+89.98% He) for adsorption for 30 min, andthen purged with He gas for 90 min until the baseline was stable todesorb the physically adsorbed ammonia gas. The sample was heated to600° C. at a heating rate of 10° C./min for desorption, and held for 30min. Then, the desorption was stopped. The TCD detector was used todetect the change of the gas composition, and the total acid content andthe strong acid content were obtained via automatic integration by theinstrument. The acid center of the strong acid was specified as the acidcenter having a corresponding NH₃ desorption temperature of greater than300° C.

In the present application, the D value is calculated as follows.

In the TEM, a crystal grain was selected, which had a crystal faceforming a polygon that had a geometric center, an edge, and a distance Hthat was 10% of the distance from the geometric center to a certainpoint at the edge (i.e. different points at the edge having different Hvalues). A region of greater than 100 square nanometers within an inwarddistance H from the edge of the crystal face, and another region ofgreater than 100 square nanometers within an outward distance H from thegeometric center of the crystal face were arbitrarily selected, thealuminum content therein was determined, respectively, as A1(S1) andA1(C1), and a calculation was conducted according to the equationD(A1)=A1(S1)/A1(C1). Five different crystal grains were selected andmeasured, and the average value was calculated and recorded as D(A1).The method for determining D(M) is similar to the above method fordetermining D(A1).

In the present application, the dry weight is determined as follows.

The molecular sieve or catalyst to be tested was placed in a mufflefurnace and calcined in an air atmosphere at 600° C. for 3 hours, andthe resulting calcined product was cooled to room temperature in aclosed drying dish, and then weighed.

The adsorption desulfurization catalysts used in the following examplesand comparative examples were produced by the Catalyst Branch of ChinaPetroleum & Chemical Corporation under the trade name FCAS. Thearomatization catalysts used included a laboratory-made catalyst, namedOTAZ-C-3, and a commercial aromatization catalyst available from theCatalyst Branch of China Petroleum & Chemical Corporation under thetrade name MP051. The properties of each catalyst used in the examplesare shown in Table 1.

TABLE 1 Properties of each catalyst used in the examples Catalyst FCASOTAZ-C-3 MP051 Chemical composition, wt % Alumina 13 50.3 50.8 Sodiumoxide / / / Nickel oxide 21 / / Zinc oxide 52 / / Gallium oxide / 1.5 /Silica 14 48.14 48.7 Apparent density, kg/m³ 1010 800 790 Pore volume,mL/g / 0.27 0.23 Specific surface area, m²/g / 218 215 Abrasion index,wt % · h⁻¹ / 1.5 1.4 Size distribution, wt % 0-40 μm 14.5 13.9 15 40-80μm 51.9 49.5 50.5 >80 μm 33.6 36.6 34.5 Micro-activity / 80 80

The process for preparing the aromatization catalyst OTAZ-C-3 is asfollows.

The starting materials used included kaolin clay (available from ChinaKaolin Clay Co., Ltd of Suzhou, solid content: 75% by weight), andpseudo-boehmite (available from Shandong Aluminum Co., Ltd., solidcontent: 65% by weight, peptized with a hydrochloric acid solutionhaving a concentration of 31% by weight before use, the molar ratio ofhydrochloric acid to the pseudo-boehmite, on the basis of alumina, being0.20).

The crystallized ZSM-5 molecular sieve (available from Qilu CatalystBranch, produced by amine-free method, n(SiO₂)/n(Al₂O₃)=27) was filteredoff the mother liquor, washed with water until the Na₂O content was lessthan 3.0% by weight, and filtered to obtained a filter cake. 100 g (drybasis) of the above molecular sieve was added to 1000 g of 2.0% NaOHsolution, heated to 65° C., reacted for 30 min, rapidly cooled to roomtemperature, filtered, and washed until the filtrate was neutral. Then,the filter cake was added to 800 g of water to make a slurry, to which40 g of NH₄Cl was added, and the mixture was heated to 75° C. After 1hour of ion exchange, an Na₂O content less than 0.2% by weight wasobtained. The resultant was filtered, and washed to obtain a molecularsieve filter cake. 50 g (dry basis) of the above molecular sieve wasadded with water to produce a molecular sieve slurry with a solidcontent of 10% by weight. 11 g of oxalic acid was added with stirring,and then 110 g of hydrochloric acid (10% by mass) and 92 g offluorosilicic acid (3% by mass) were added co-currently within 30 min.The resultant was heated to 65° C. and stirred at a constant temperaturefor 1 h, filtered and washed with water until the filtrate was neutral.The filter cake was added with water to make a molecular sieve slurryhaving a solid content of 45% by weight. 1.2 g of H₃PO₄ (having aconcentration of 85% by weight) and 3.3 g of Zn(NO₃)₂.6H₂O weredissolved in 10 g of water, added with ammonia water to provide a pH of6, and then added to the molecular sieve slurry and mixed uniformly. Themixture was dried, and calcined at 550° C. for 2 h under 100% steamatmosphere to obtain a molecular sieve A, the properties of which arelisted in Table 2.

The pseudo-boehmite was mixed with the kaolin clay and formulated into aslurry having a solid content of 30% by weight with deionized water, andstirred uniformly, and the pH of the slurry was adjusted to 2.5 withhydrochloric acid. The mixture was held at the pH and allowed to standat 50° C. for 1 hour for aging, and stirred for another 1 hour to form acolloid. The prepared molecular sieve A and water were added to form acatalyst slurry (solid content of 35% by weight). The stirring wascontinued, followed by spray drying to obtain a microsphere catalyst.The microsphere catalyst was then calcined at 500° C. for 1 hour toobtain the aromatization catalyst OTAZ-C-3 used in the presentapplication, which had a dry basis composition of 25% by weight ofkaolin clay, 25% by weight of pseudo-boehmite and 50% by weight of themolecular sieve A.

TABLE 2 Properties of the molecular sieve A Item Molecular sieve ADegree of crystallinity/% 90 n(SiO₂)/n(Al₂O₃) 110 P₂O₅ content/% 1.5Content of supported metal oxide/% 1.6 S_(BET)/(m²/g) 440(V_(mesopore)/V_(total pore))/% 60 (V_(2 nm-20 nm)/V_(mesopore))/% 99(Strong acid content/total acid content)/% 70 B acid content/L acidcontent 35 D(Al) 0.77 D(M) 3.6

The passivation of the aromatization catalyst is performed as follows.

1. The fresh aromatization catalyst OTAZ-C-3 was charged into adense-phase fluidized bed reactor, and contacted with stabilizedgasoline A at a passivation temperature of 410° C. for 2 hours to obtaina passivated OTAZ-C-3 catalyst having a content of passivated species of0.5% by weight and a micro-activity of 35.

2. The fresh aromatization catalyst MP051 was charged into a dense-phasefluidized bed reactor, and contacted with stabilized gasoline A at apassivation temperature of 410° C. for 2 hours to obtain a passivatedMP051 catalyst having a content of passivated species of 0.5% by weightand a micro-activity of 35.

The aging treatment of the aromatization catalyst is performed asfollows.

1. The fresh aromatization catalyst OTAZ-C-3 was charged into adense-phase fluidized bed reactor, and continuously aged for 8 hoursunder an aging temperature of 780° C. and 100% steam atmosphere toobtain an aged OTAZ-C-3 catalyst with a micro-activity of 35.

2. The fresh aromatization catalyst MP051 was charged into a dense-phasefluidized bed reactor and continuously aged for 8 hours under an agingtemperature of 780° C. and 100% steam atmosphere to obtain an aged MP051catalyst with a micro-activity of 35.

In each example and comparative example of the present application, thecontents of Na₂O, NiO, ZnO, Ga₂O₃, Al₂O₃, and SiO₂ in the catalysts weredetermined by the X-ray fluorescence method according to GB/T30905-2014.

In each example and comparative example of the present application, thecontent of the passivated species in the passivated aromatizationcatalyst was determined according to the RIPP 107-90 method, of whichthe steps are summarized as follows: the sample was burned in a highfrequency furnace to generate CO₂ and CO gases, and the gases wereintroduced into an infrared detector through a filter drier to obtain atotal carbon content expressed in percentage. Since the catalyst itselfhad no induction effect, it was necessary to add a sensing agent, afluxing agent to promote the burning of the sample; and since the samplewas porous and had a water absorption capability, it was necessary to bepretreated before the test. Particularly, the test procedure included:

1. Test preparation: Preheating, cleaning, leak testing and checking ofthe circuit were performed according to the operation procedures ofCS-46 Carbon Sulfur Tester (manufactured by American LECO company). Thecatalyst sample was baked at 110° C. for 2-3 hours and then cooled toroom temperature in a desiccator.

2. Testing: A standard copper sample was burned, the C % value waschecked, and the reading was adjusted to be within the error range. Acrucible was placed on an electronic balance, and the reading was resetto zero. 0.3-0.4 g of the baked catalyst sample was added, and thesample weight was automatically input to the tester. The crucible wasremoved, added with a tin foil and then put back on the electronicbalance, and the reading was reset to zero. 1.5-1.6 g of copper flux(available from Shandong Metallurgical Research Institute) was added.The crucible was removed and covered with a cap, and then put on aburning seat with crucible tongs. After burning for 30 seconds, thereading indicator light was on, and the C % value was recorded. Eachsample was assayed for two times. The carbon blank value for this testwas determined by the same procedure. The carbon content of the catalystwas calculated as follows: C %=C % of the sample—the blank C %.

In each example and comparative example of the present application, themicro-activity of the aromatization catalyst was determined according tothe RIPP 92-90 method, using the same equipment and test procedure asASTM D3907-2013, under the following conditions: feedstock oil: Dagangstraight-run diesel having a relative density d₄ ²⁰ of 0.8419, aninitial boiling point of 235° C., a dry point of 337° C.; reactionconditions: an oil intake of 1.56 g, a reaction temperature of 460° C.,a catalyst-to-oil mass ratio of 3.2, a weight hourly space velocity ofthe feedstock oil of 16 h⁻¹ and a feed time of 70 seconds.

In each example and comparative example of the present application, theoctane number RON and MON of gasoline were determined according to thestandard methods of GB/T 5487-1995 and GB/T 503-1995, respectively, andthe antiknock index was calculated by (MON+RON)/2, the PONA of gasolinewas analyzed by simulated distillation and the hydrocarbon compositionanalysis of gasoline (determined according to the test methods of ASTMD2887 and ASTM D6733-01 (2011), respectively), and the sulfur content ofgasoline was determined according to SH/T0689-2000.

Examples I-II Splitting of Gasoline Feedstock and Etherification ofLight Gasoline Fraction

The full-range gasoline feedstocks used in Example I and Example II werestabilized gasolines A and B, respectively, and their properties arelisted in Table 3.

The stabilized gasolines A and B were separately distilled in afractionation column, split into light fractions and heavy fractions,and the light fractions were controlled to have a final boiling point of65-70° C. (according to ASTM D86 standard). The light gasoline fractionobtained by the distillation of the stabilized gasoline A was designatedas LCN-A, and the heavy gasoline fraction thus obtained was designatedas HCN-A. The light gasoline fraction obtained by the distillation ofthe stabilized gasoline B was designated as LCN-B, and the heavygasoline fraction thus obtained was designated as HCN-B. The propertiesof the light gasoline fractions and the heavy gasoline fractionsobtained by the distillation of the stabilized gasolines A and B areshown in Table 4.

The light gasoline fractions LCN-A and LCN-B were separately subjectedto a pretreatment including desulfurization and removal of dienes in thepresence of hydrogen in a refining reactor, so that the sulfur contentand the diene content of the light gasoline fractions were all reducedto below 10 ppm, and then mixed with methanol (analytically pure) andsent into an etherification reactor for etherification. Theetherification conditions included a reaction temperature of 55-80° C.,a space velocity of 1.2 h⁻¹, a molar ratio of methanol to active olefinsin the light gasoline fraction of 1.2, and an etherification catalyst ofstrongly acidic cation-exchange resin (732 type, styrene-based). Afterthe etherification reaction, the resulting oil and gas were introducedinto an etherification product fractionation column for separation. Amethanol-containing tail gas comprising residual C5 compounds and thealcohol was obtained at the top of the column, and an etherified oil wasobtained at the bottom of the column. The temperature at the top of theetherification product fractionation column was 60-80° C., and thetemperature at the bottom was 110-140° C. The corresponding etherifiedoils obtained were designated as LCN-A-M and LCN-B-M, respectively, andtheir properties are also shown in Table 4.

TABLE 3 Properties of the gasoline feedstocks used in the examplesStabilized Stabilized Gasoline feedstock gasoline A gasoline B Densityat 20° C., kg/m³ 737.3 743.9 Refractive index at 20° C. 1.4212 1.4229Vapor pressure (RVPE), kPa 49 50 Carbon content, % (w) 86.36 86.37Hydrogen content, % (w) 13.64 13.63 Sulfur content, mg/L 421 138Nitrogen content, mg/L 139 35 Induction period, min 667 >1000 Groupcomposition (FIA method) Aromatics, % (by volume) 15.4 20.2 Olefins, %(by volume) 54.9 30.9 Saturated hydrocarbons, % (by volume) 29.7 48.9Measured RON 90.9 88.6 Measured MON 78.9 78.7 (RON + MON)/2 84.9 83.7Distillation range under normal pressure, ° C. IBP 44 44 5% (φ) 59 5610% (φ) 63 63 30% (φ) 80 82 50% (φ) 106 108 70% (φ) 139 140 90% (φ) 175174 FBP 204 199

TABLE 4 Properties of the fractions and etherified oils obtained inExamples I-II Experimental scheme Example I Example II Name of thefraction LCN-A HCN-A LCN-B HCN-B Percentage relative to 22 78 20.5 79.5the full-range stabilized gasoline, % Density at 20° C., kg/m³ 647.7760.7 653.5 767.5 Total sulfur content, mg/L 23 527 18 189 Groupcomposition (FIA method) Aromatics, % (by volume) 0 22.6 0 30.2 Olefins,% (by volume) 65.1 45.1 60.8 27.9 Saturated hydrocarbons, 34.9 32.3 38.241.9 % (by volume) Name of the etherified oil LCN-A-M / LCN-B-M /Percentage relative to 25.5 / 23.3 / the full-range stabilized gasoline,% Group composition (FIA method) Aromatics, % (by volume) 0 / 0 /Olefins, % (by volume) 13.0 / 15.2 / Saturated hydrocarbons, 32.5 / 33.3/ % (by volume)

The following Examples I-1 to I-10 are working examples in which theheavy gasoline fraction HCN-A was used as the feedstock, and varioustypes of catalysts were used for the desulfurization and aromatization,and the results are shown in Table 5.

Example I-1

The heavy gasoline fraction HCN-A was contacted with a mixed catalystcomprising the adsorption desulfurization catalyst FCAS and thepassivated OTAZ-C-3 catalyst in a small continuous fluidized bed reactorfor adsorption desulfurization and aromatization, in which the OTAZ-C-3catalyst was present in an amount of 7% by weight based on the totalweight of the mixed catalyst.

The operating conditions were as follows: a reaction temperature of 400°C., a reactor pressure of 2.1 MPa, a weight hourly space velocity of theheavy gasoline fraction of 6 h⁻¹, and a volume ratio of hydrogen to theheavy gasoline fraction of 75. The desulfurization-aromatization productobtained from the top of the reactor was cooled to about 10° C., andseparated to obtain an off-gas and a heavy gasoline product (designatedas HCN-A heavy gasoline product, the same below, the properties areshown in Table 5). The regeneration temperature of the mixed catalystwas 550° C., and, after the regeneration, the mixed catalyst wasreturned to the reactor for recycling.

Example I-2

The heavy gasoline fraction HCN-A was contacted with a mixed catalystcomprising the adsorption desulfurization catalyst FCAS and the agedOTAZ-C-3 catalyst in a small continuous fluidized bed reactor to carryout adsorption desulfurization and aromatization, in which the OTAZ-C-3catalyst is present in an amount of 7% by weight based on the totalweight of the mixed catalyst.

The operating conditions were as follows: a reaction temperature of 400°C., a reactor pressure of 2.1 MPa, a weight hourly space velocity of theheavy gasoline fraction of 6 h⁻¹, and a volume ratio of hydrogen to theheavy gasoline fraction of 75. The desulfurization-aromatization productobtained from the top of the reactor was cooled to about 10° C., andseparated to obtain an off-gas and a heavy gasoline product (designatedas HCN-A heavy gasoline product, the same below, the properties areshown in Table 5). The regeneration temperature of the mixed catalystwas 550° C., and, after the regeneration, the mixed catalyst wasreturned to the reactor for recycling.

Example I-3

The operation was substantially the same as in Example I-1, except thatthe passivated OTAZ-C-3 catalyst was replaced with an equivalent weightof fresh OTAZ-C-3 catalyst, and the properties of the resulting HCN-Aheavy gasoline product are listed in Table 5.

Example I-4

The operation was substantially the same as in Example I-1, except thatthe passivated OTAZ-C-3 catalyst was replaced with an equivalent weightof a mixed OTAZ-C-3 catalyst (comprising 5% by weight of fresh catalystand 95% by weight of passivated catalyst, based on the weight of thearomatization catalyst), and the properties of the resulting HCN-A heavygasoline product are listed in Table 5.

Example I-5

The operation was substantially the same as in Example I-2, except thatthe aged OTAZ-C-3 catalyst was replaced with an equivalent weight of amixed OTAZ-C-3 catalyst (comprising 5% by weight of fresh catalyst and95% by weight of aged catalyst, based on the weight of the aromatizationcatalyst), and the properties of the resulting HCN-A heavy gasolineproduct are listed in Table 5.

Example I-6

The operation was substantially the same as in Example I-1, except thatthe passivated OTAZ-C-3 catalyst was replaced with an equivalent weightof the passivated MP051 catalyst, and the properties of the resultingHCN-A heavy gasoline product are listed in table 5.

Example I-7

The operation was substantially the same as in Example I-2, except thatthe aged OTAZ-C-3 catalyst was replaced with an equivalent weight of theaged MP051 catalyst, and the properties of the resulting HCN-A heavygasoline product are listed in Table 5.

Example I-8

The operation was substantially the same as in Example I-1, except thatthe passivated OTAZ-C-3 catalyst was replaced with an equivalent weightof fresh MP051 catalyst, and the properties of the resulting HCN-A heavygasoline product are listed in Table 5.

Example I-9

The operation was substantially the same as in Example I-1, except thatthe passivated OTAZ-C-3 catalyst was replaced with an equivalent weightof mixed MP051 catalyst (comprising 5% by weight of fresh catalyst and95% by weight of passivated catalyst, based on the weight of thearomatization catalyst), and the properties of the resulting HCN-A heavygasoline product are listed in Table 5.

Example I-10

The operation was substantially the same as in Example I-2, except thatthe aged OTAZ-C-3 catalyst was replaced with an equivalent weight ofmixed MP051 catalyst (comprising 5% by weight of fresh catalyst and 95%by weight of aged catalyst, based on the weight of the aromatizationcatalyst), and the properties of the resulting HCN-A heavy gasolineproduct are listed in Table 5.

Comparative Example I-1

The operation was substantially the same as in Example 1, except thatthe passivated OTAZ-C-3 catalyst was replaced with an equivalent weightof the adsorption desulfurization catalyst FCAS, and the properties ofthe resulting HCN-A heavy gasoline product are shown in Table 5.

TABLE 5 Results of Examples I-1 to I-10 and Comparative Example I-1Heavy gasoline Example Nos. fraction HCN-A I-1 I-2 I-3 I-4 I-5 Name ofthe / OTAZ-C-3 OTAZ-C-3 OTAZ-C-3 OTAZ-C-3 OTAZ-C-3 aromatizationcatalyst Type of the / Passivated Aged Fresh Mixed Mixed aromatizationcatalyst Micro-activity / 35 35 80 38 38 of the aromatization catalystPONA* of gasoline, wt % nP 4.13 7.09 7.21 9.06 7.21 7.16 iP 22.45 25.3926.32 28.06 26.32 26.37 O 37.74 27.42 27.01 23.12 27.01 27.21 N 6.99 98.9 8.8 8.9 8.9 A 28.27 30.82 30.4 30.76 30.4 30.2 Total 99.58 99.7299.84 99.8 99.84 99.84 Measured RON 87.2 87.5 87.2 86.1 87.1 87.1Measured MON 77.3 77.8 77.7 76.6 77.7 77.7 (RON + MON)/2 82.3 82.7 82.581.4 82.4 82.4 Change in / 0.4 0.2 −0.9 0.1 0.1 antiknock index Sulfurcontent, 692 9 9 9 9 9 ppm Example Nos. I-6 I-7 I-8 I-9 I-10 Comp. Ex.I-1 Name of the MP051 MP051 MP051 MP051 MP051 None aromatizationcatalyst Type of the Passivated Aged Fresh Mixed Mixed / aromatizationcatalyst Micro-activity of the 35 35 80 38 38 / aromatization catalystPONA of gasoline, wt % nP 7.39 7.51 9.36 7.51 7.46 7.27 iP 26.99 26.8829.06 27.32 27.37 28.04 O 26.42 26.6 22.12 26.01 26.21 26.45 N 9 9 8.88.9 8.9 9.4 A 29.92 29.74 30.46 30.1 29.9 28.62 Total 99.72 99.72 99.899.84 99.84 99.78 Measured RON 87 87 85.7 86.8 86.8 85.6 Measured MON77.6 77.6 76.4 77.5 77.5 76.2 (RON + MON)/2 82.3 82.3 81.1 82.2 82.280.9 Change in antiknock 0 0 −1.2 −0.1 −0.1 −1.4 index Sulfur content,ppm 9 9 9 9 9 9 *Note: The meaning of each symbol shown in the PONA ofgasoline is as follows: nP—normal paraffin; iP—isoparaffin; O—olefin;N—naphthene; A—aromatics.

As shown in Table 5, in Comparative Example I-1, when the heavy gasolinefraction HCN-A was treated using the adsorption desulfurization catalystFCAS only, that is, only adsorption desulfurization was carried out, theoctane number (antiknock index) of the resulting HCN-A heavy gasolineproduct was significantly lower than that of the heavy gasoline fractionHCN-A. In Examples I-6 to I-10, when the heavy gasoline fraction wastreated using a mixed catalyst comprising the adsorption desulfurizationcatalyst FCAS and the aromatization catalyst MP051, that is, bothadsorption desulfurization and aromatization were carried out, theoctane number of the resulting HCN-A heavy gasoline product was improvedas compared to Comparative Example I-1. Particularly, when anaromatization catalyst comprising a passivated or aged MP051 catalystwas used, the improvement was more remarkable. Further, in Examples I-1to I-5, when the heavy gasoline fraction was treated using a mixedcatalyst comprising the adsorption desulfurization catalyst FCAS and thearomatization catalyst OTAZ-C-3, the octane number of the resultingHCN-A heavy gasoline product was further improved as compared toExamples I-6 to I-10. Similarly, when an aromatization catalystcomprising a passivated or aged OTAZ-C-3 catalyst was used, theimprovement was more remarkable.

The following Examples II-1 to II-10 are working examples in which theheavy gasoline fraction HCN-B was used as the feedstock, and varioustypes of catalysts were used for the desulfurization and aromatization,and the results are shown in Table 6.

Example II-1

The operation was substantially the same as in Example I-1, except thatthe heavy gasoline fraction HCN-B was used in place of the heavygasoline fraction HCN-A, and the operating conditions were as follows: areaction temperature of 400° C., a reactor pressure of 1.8 MPa, a weighthourly space velocity of the heavy gasoline fraction of 8 h⁻¹, and avolume ratio of hydrogen to the heavy gasoline fraction of 60. Theproperties of the resulting HCN-B heavy gasoline product are listed inTable 6.

Example II-2

The operation was substantially the same as in Example I-2, except thatthe heavy gasoline fraction HCN-B was used in place of the heavygasoline fraction HCN-A, and the operating conditions were as follows: areaction temperature of 400° C., a reactor pressure of 1.8 MPa, a weighthourly space velocity of the heavy gasoline fraction of 8 h⁻¹, and avolume ratio of hydrogen to the heavy gasoline fraction of 60. Theproperties of the resulting HCN-B heavy gasoline product are listed inTable 6.

Example II-3

The operation was substantially the same as in Example I-3, except thatthe heavy gasoline fraction HCN-B was used in place of the heavygasoline fraction HCN-A, and the operating conditions were as follows: areaction temperature of 400° C., a reactor pressure of 1.8 MPa, a weighthourly space velocity of the heavy gasoline fraction of 8 h⁻¹, and avolume ratio of hydrogen to the heavy gasoline fraction of 60. Theproperties of the resulting HCN-B heavy gasoline product are listed inTable 6.

Example II-4

The operation was substantially the same as in Example I-4, except thatthe heavy gasoline fraction HCN-B was used in place of the heavygasoline fraction HCN-A, and the operating conditions were as follows: areaction temperature of 400° C., a reactor pressure of 1.8 MPa, a weighthourly space velocity of the heavy gasoline fraction of 8 h⁻¹, and avolume ratio of hydrogen to the heavy gasoline fraction of 60. Theproperties of the resulting HCN-B heavy gasoline product are listed inTable 6.

Example II-5

The operation was substantially the same as in Example I-5, except thatthe heavy gasoline fraction HCN-B was used in place of the heavygasoline fraction HCN-A, and the operating conditions were as follows: areaction temperature of 400° C., a reactor pressure of 1.8 MPa, a weighthourly space velocity of the heavy gasoline fraction of 8 h⁻¹, and avolume ratio of hydrogen to the heavy gasoline fraction of 60. Theproperties of the resulting HCN-B heavy gasoline product are listed inTable 6.

Example II-6

The operation was substantially the same as in Example I-6, except thatthe heavy gasoline fraction HCN-B was used in place of the heavygasoline fraction HCN-A, and the operating conditions were as follows: areaction temperature of 400° C., a reactor pressure of 1.8 MPa, a weighthourly space velocity of the heavy gasoline fraction of 8 h⁻¹, and avolume ratio of hydrogen to the heavy gasoline fraction of 60. Theproperties of the resulting HCN-B heavy gasoline product are listed inTable 6.

Example II-7

The operation was substantially the same as in Example I-7, except thatthe heavy gasoline fraction HCN-B was used in place of the heavygasoline fraction HCN-A, and the operating conditions were as follows: areaction temperature of 400° C., a reactor pressure of 1.8 MPa, a weighthourly space velocity of the heavy gasoline fraction of 8 h⁻¹, and avolume ratio of hydrogen to the heavy gasoline fraction of 60. Theproperties of the resulting HCN-B heavy gasoline product are listed inTable 6.

Example II-8

The operation was substantially the same as in Example I-8, except thatthe heavy gasoline fraction HCN-B was used in place of the heavygasoline fraction HCN-A, and the operating conditions were as follows: areaction temperature of 400° C., a reactor pressure of 1.8 MPa, a weighthourly space velocity of the heavy gasoline fraction of 8 h⁻¹, and avolume ratio of hydrogen to the heavy gasoline fraction of 60. Theproperties of the resulting HCN-B heavy gasoline product are listed inTable 6.

Example II-9

The operation was substantially the same as in Example I-9, except thatthe heavy gasoline fraction HCN-B was used in place of the heavygasoline fraction HCN-A, and the operating conditions were as follows: areaction temperature of 400° C., a reactor pressure of 1.8 MPa, a weighthourly space velocity of the heavy gasoline fraction of 8 h⁻¹, and avolume ratio of hydrogen to the heavy gasoline fraction of 60. Theproperties of the resulting HCN-B heavy gasoline product are listed inTable 6.

Example II-10

The operation was substantially the same as in Example I-10, except thatthe heavy gasoline fraction HCN-B was used in place of the heavygasoline fraction HCN-A, and the operating conditions were as follows: areaction temperature of 400° C., a reactor pressure of 1.8 MPa, a weighthourly space velocity of the heavy gasoline fraction of 8 h⁻¹, and avolume ratio of hydrogen to the heavy gasoline fraction of 60. Theproperties of the resulting HCN-B heavy gasoline product are listed inTable 6.

Comparative Example II-1

The operation was substantially the same as in Comparative Example I-1,except that the heavy gasoline fraction HCN-B was used in place of theheavy gasoline fraction HCN-A, and the operating conditions were asfollows: a reaction temperature of 400° C., a reactor pressure of 1.8MPa, a weight hourly space velocity of the heavy gasoline fraction of 8h⁻¹, and a volume ratio of hydrogen to the heavy gasoline fraction of60. The properties of the resulting HCN-B heavy gasoline product arelisted in Table 6.

TABLE 6 Results of Examples II-1 to II-10 and Comparative Example II-1Heavy gasoline Example Nos. fraction HCN-B II-1 II-2 II-3 II-4 II-5 Nameof the / OTAZ-C-3 OTAZ-C-3 OTAZ-C-3 OTAZ-C-3 OTAZ-C-3 aromatizationcatalyst Type of the / Passivated Aged Fresh Mixed Mixed aromatizationcatalyst Micro-activity of the / 35 35 80 38 38 aromatization catalystPONA of gasoline, wt % nP 3.14 5.2 5.5 7.1 5.5 5.6 iP 28.83 30.39 31.4633.06 31.46 31.36 O 24.12 17.66 16.95 13.38 16.95 17.15 N 12.28 12.2312.13 12.13 12.13 12.13 A 31.17 34.3 33.72 34.1 33.72 33.52 Total 99.5499.78 99.76 99.77 99.76 99.76 Measured RON 85.2 86.4 86.1 84.9 86 86Measured MON 77.3 78.4 78.2 77.2 78.2 78.2 (RON + MON)/2 81.3 82.4 82.281.1 82.1 82.1 Change in antiknock / 1.1 0.9 −0.2 0.8 0.8 index Sulfurcontent, ppm 246 6 6 6 6 6 Example Nos. II-6 II-7 II-8 II-9 II-10 Comp.Ex. II-1 Name of the MP051 MP051 MP051 MP051 MP051 None aromatizationcatalyst Type of the Passivated Aged Fresh Mixed Mixed / aromatizationcatalyst Micro-activity of the 35 35 80 38 38 / aromatization catalystPONA of gasoline, wt % nP 5.5 5.7 7.4 5.8 5.9 4.1 iP 31.99 31.78 34.0632.46 32.36 33.05 O 16.66 16.99 12.38 15.95 16.15 16.65 N 12.23 12.212.13 12.13 12.13 13.65 A 33.4 33.11 33.8 33.42 33.22 32.09 Total 99.7899.78 99.77 99.76 99.76 99.54 Measured RON 86 86 84.7 85.7 85.7 84.5Measured MON 78.2 78.2 77 78 78 77 (RON + MON)/2 82.1 82.1 80.9 81.981.9 80.8 Change in antiknock 0.8 0.8 −0.4 0.6 0.6 −0.5 index Sulfurcontent, ppm 6 6 6 6 6 6

Similar to the results of Examples I-1 to I-10, as shown in Table 6, inComparative Example II-1, when the heavy gasoline fraction HCN-B wastreated using the adsorption desulfurization catalyst FCAS only, thatis, only adsorption desulfurization was carried out, the octane number(antiknock index) of the resulting HCN-B heavy gasoline product wassignificantly lower than that of the heavy gasoline fraction HCN-B. InExamples II-6 to II-10, when the heavy gasoline fraction was treatedusing a mixed catalyst comprising the adsorption desulfurizationcatalyst FCAS and the aromatization catalyst MP051, that is, bothadsorption desulfurization and aromatization were carried out, theoctane number of the resulting HCN-B heavy gasoline product was improvedas compared to Comparative Example II-1. Particularly, when anaromatization catalyst comprising a passivated or aged MP051 catalystwas used, the improvement was more remarkable. Further, in Examples II-1to II-5, when the heavy gasoline fraction was treated using a mixedcatalyst comprising the adsorption desulfurization catalyst FCAS and thearomatization catalyst OTAZ-C-3, the octane number of the resultingHCN-B heavy gasoline product was further improved as compared toExamples II-6 to II-10. Similarly, when an aromatization catalystcomprising a passivated or aged OTAZ-C-3 catalyst was used, theimprovement was more remarkable.

The following Examples III-1 to III-12 are working examples in which aHCN-A or HCN-B heavy gasoline product was mixed with the correspondingetherified oil LCN-AM or LCN-BM to obtain a gasoline product, and theresults are shown in Table 7.

Example III-1

The HCN-A heavy gasoline product obtained in Example I-1 was mixed withthe etherified oil LCN-A-M to obtain a high-octane clean gasolineproduct, the properties of which are shown in Table 7.

Example III-2

The HCN-A heavy gasoline product obtained in Example I-2 was mixed withthe etherified oil LCN-A-M to obtain a high-octane clean gasolineproduct, the properties of which are shown in Table 7.

Example III-3

The HCN-A heavy gasoline product obtained in Example I-3 was mixed withthe etherified oil LCN-A-M to obtain a high-octane clean gasolineproduct, the properties of which are shown in Table 7.

Example III-4

The HCN-A heavy gasoline product obtained in Example I-4 was mixed withthe etherified oil LCN-A-M to obtain a high-octane clean gasolineproduct, the properties of which are shown in Table 7.

Example III-5

The HCN-A heavy gasoline product obtained in Example I-5 was mixed withthe etherified oil LCN-A-M to obtain a high-octane clean gasolineproduct, the properties of which are shown in Table 7.

Example III-6

The HCN-A heavy gasoline product obtained in Example I-6 was mixed withthe etherified oil LCN-A-M to obtain a high-octane clean gasolineproduct, the properties of which are shown in Table 7.

Example III-7

The HCN-A heavy gasoline product obtained in Example I-7 was mixed withthe etherified oil LCN-A-M to obtain a high-octane clean gasolineproduct, the properties of which are shown in Table 7.

Example III-8

The HCN-A heavy gasoline product obtained in Example I-8 was mixed withthe etherified oil LCN-A-M to obtain a high-octane clean gasolineproduct, the properties of which are shown in Table 7.

Example III-9

The HCN-A heavy gasoline product obtained in Example I-9 was mixed withthe etherified oil LCN-A-M to obtain a high-octane clean gasolineproduct, the properties of which are shown in Table 7.

Example III-10

The HCN-A heavy gasoline product obtained in Example I-10 was mixed withthe etherified oil LCN-A-M to obtain a high-octane clean gasolineproduct, the properties of which are shown in Table 7.

Example III-11

The HCN-B heavy gasoline product obtained in Example II-1 was mixed withthe etherified oil LCN-B-M to obtain a high-octane clean gasolineproduct, the properties of which are shown in Table 7.

Example III-12

The HCN-B heavy gasoline product obtained in Example II-2 was mixed withthe etherified oil LCN-B-M to obtain a high-octane clean gasolineproduct, the properties of which are shown in Table 7.

Comparative Example III-1

The HCN-A heavy gasoline product obtained in Comparative Example I-1 wasmixed with the etherified oil LCN-A-M to obtain a gasoline product, theproperties of which are shown in Table 7.

Comparative Example III-2

The HCN-B heavy gasoline product obtained in Comparative Example II-1was mixed with the etherified oil LCN-B-M to obtain a gasoline product,the properties of which are shown in Table 7.

TABLE 7 Results of Examples III-1 to III-12 and Comparative ExamplesIII-1 and III-2 Example Nos. III-1 III-2 III-3 III-4 III-5 Name of thearomatization catalyst OTAZ-C-3 OTAZ-C-3 OTAZ-C-3 OTAZ-C-3 OTAZ-C-3 Typeof the aromatization catalyst Passivated Aged Fresh Mixed Mixed Type ofthe gasoline feedstock A A A A A Etherification of the light gasolineYes Yes Yes Yes Yes fraction (Yes/No) Gasoline yield relative to the102.3 102.3 101 102.1 102.1 feedstock, % Density at 20° C., kg/m³ 740.6740.6 740.8 740.6 740.6 Refractive index at 20° C. 1.4146 1.4146 1.41311.4146 1.4146 Vapor pressure (RVPE), kPa 62 62 66 62 62 Carbon content,% (w) 85.84 85.84 85.95 85.84 85.84 Hydrogen content, % (w) 14.16 14.1614.05 14.16 14.16 Sulfur content, mg/L 15 14 13 15 14 Nitrogen content,mg/L 57 55 55 57 55 Benzene, % (by volume) 0.3 0.3 0.3 0.3 0.3 Groupcomposition (FIA method) Aromatics, % (by volume) 19.8 19.1 19.3 19.219.1 Olefins, % (by volume) 20.3 20.4 18.3 20 20.1 Saturatedhydrocarbons, % 45.5 46.4 48 46.4 46.7 (by volume) Oxygen content, % (bymass) 2.3 2.3 2.2 2.3 2.3 Measured RON 90.8 90.8 89.2 90.7 90.7 MeasuredMON 80 80 79 80 80 (RON + MON)/2 85.4 85.4 84.1 85.35 85.35 Change inantiknock index 0.5 0.5 −0.8 0.45 0.45 Distillation range under normalpressure, ° C. IBP 35 35 35 35 35 5% (φ) 53.7 54 54 53.7 54 10% (φ) 6262 63 62 62 30% (φ) 80.6 81 82 80.6 81 50% (φ) 99.1 99 99 99.1 99 70%(φ) 127.7 128 128 127.7 128 90% (φ) 173 173 173 173 173 FBP 205 204 204205 204 Example Nos. III-6 III-7 III-8 III-9 III-10 Name of thearomatization catalyst MP051 MP051 MP051 MP051 MP051 Type of thearomatization catalyst Passivated Aged Fresh Mixed Mixed Type of thegasoline feedstock A A A A A Etherification of the light gasoline YesYes Yes Yes Yes fraction (Yes/No) Gasoline yield relative to the 102 102100.7 101.8 101.8 feedstock, % Density at 20° C., kg/m³ 740.6 740.6740.8 740.6 740.6 Refractive index at 20° C. 1.4146 1.4146 1.4131 1.41461.4146 Vapor pressure (RVPE), kPa 63 63 66 63 63 Carbon content, % (w)85.84 85.84 85.95 85.84 85.84 Hydrogen content, % (w) 14.16 14.16 14.0514.16 14.16 Sulfur content, mg/L 15 14 13 15 14 Nitrogen content, mg/L57 55 55 57 55 Benzene, % (by volume) 0.3 0.3 0.3 0.3 0.3 Groupcomposition (FIA method) Aromatics, % (by volume) 19.2 19.1 19.3 19.219.1 Olefins, % (by volume) 18.8 19.9 17.8 19.8 19.9 Saturatedhydrocarbons, % 46.6 46.9 48.5 46.6 46.9 (by volume) Oxygen content, %(by mass) 2.3 2.3 2.2 2.3 2.3 Measured RON 90.3 90.3 89 90.2 90.2Measured MON 79.5 79.5 79 79.5 79.5 (RON + MON)/2 84.9 84.9 84 84.8584.85 Change in antiknock index 0 0 −0.9 −0.05 −0.05 Distillation rangeunder normal pressure, ° C. IBP 35 35 35 35 35 5% (φ) 53.7 54 54 53.7 5410% (φ) 62 62 63 62 62 30% (φ) 80.6 81 82 80.6 81 50% (φ) 99.1 99 9999.1 99 70% (φ) 127.7 128 128 127.7 128 90% (φ) 173 173 173 173 173 FBP205 204 204 205 204 Example Nos. Comp. Ex. Comp. Ex. III-11 III-12 III-1III-2 Name of the aromatization catalyst OTAZ-C-3 OTAZ-C-3 None NoneType of the aromatization catalyst Passivated Aged / / Type of thegasoline feedstock B B A B Etherification of the light gasoline Yes YesYes Yes fraction (Yes/No) Gasoline yield relative to the 101.8 101.8 102101.5 feedstock, % Density at 20° C., kg/m³ 739.5 739.5 742.1 741.5Refractive index at 20° C. 1.4153 1.4153 1.4138 1.4154 Vapor pressure(RVPE), kPa 61 61 36.3 39.3 Carbon content, % (w) 85.91 85.91 85.6 85.76Hydrogen content, % (w) 14.09 14.09 14.4 14.24 Sulfur content, mg/L 1110 14 10 Nitrogen content, mg/L 20 20 57 26 Benzene, % (by volume) 0.50.5 0.3 0.5 Group composition (FIA method) Aromatics, % (by volume) 22.421.6 17.2 19 Olefins, % (by volume) 13.2 13.5 17.1 14.5 Saturatedhydrocarbons, % 54 54.3 51 56.2 (by volume) Oxygen content, % (by mass)1.7 1.7 2.3 1.7 Measured RON 88.8 88.8 88.9 88.5 Measured MON 79.6 79.678.9 78.5 (RON + MON)/2 84.2 84.2 83.9 83.5 Change in antiknock index0.5 0.5 −1.0 −0.2 Distillation range under normal pressure, ° C. IBP32.9 33 46.2 41.2 5% (φ) 50 50 64.4 59.6 10% (φ) 55.4 56 70.4 65 30% (φ)76 76 84.6 81.3 50% (φ) 100 100 100.9 101.4 70% (φ) 130.4 130 128.7129.7 90% (φ) 170.4 170 171.7 169.5 FBP 203.1 203 205 203.2

As shown in Table 7, in the case where a heavy gasoline product wasmixed with the etherified oil to obtain a gasoline product, only theoctane number (antiknock index) of the gasoline products obtained inComparative Examples III-1 and III-2 using the adsorptiondesulfurization catalyst FCAS alone was significantly lowered ascompared to the gasoline feedstock. The octane number of the gasolineproducts obtained in Examples III-6 to III-10 using a mixed catalystcomprising the adsorption desulfurization catalyst FCAS and thearomatization catalyst MP051 was improved as compared to ComparativeExample III-1. Particularly, when an aromatization catalyst comprising apassivated or aged MP051 catalyst was used, the improvement was moreremarkable. Further, the octane number of the gasoline products obtainedin Examples III-1 to III-5 using a mixed catalyst comprising theadsorption desulfurization catalyst FCAS and the aromatization catalystOTAZ-C-3 was further improved as compared to Examples III-6 to III-10,and when an aromatization catalyst comprising a passivated or agedOTAZ-C-3 catalyst was used, the improvement was more remarkable.Similarly, as compared to Comparative Example III-2 using only theadsorption desulfurization catalyst, the gasoline products obtained inExamples III-11 and III-12 using a mixed catalyst showed a significantimproved octane number.

The following Examples IV-1 to IV-5 are working examples in which aHCN-A heavy gasoline product was mixed with a light gasoline fractionLCN-A to obtain a gasoline product, and the results are shown in Table8.

Example IV-1

The HCN-A heavy gasoline product obtained in Example I-6 was mixed withthe light gasoline fraction LCN-A to obtain a gasoline product, theproperties of which are shown in Table 8.

Example IV-2

The HCN-A heavy gasoline product obtained in Example I-7 was mixed withthe light gasoline fraction LCN-A to obtain a gasoline product, theproperties of which are shown in Table 8.

Example IV-3

The HCN-A heavy gasoline product obtained in Example I-8 was mixed withthe light gasoline fraction LCN-A to obtain a gasoline product, theproperties of which are shown in Table 8.

Example IV-4

The HCN-A heavy gasoline product obtained in Example I-9 was mixed withthe light gasoline fraction LCN-A to obtain a gasoline product, and theproperties are shown in Table 8.

Example IV-5

The HCN-A heavy gasoline product obtained in Example I-10 was mixed withthe light gasoline fraction LCN-A to obtain a gasoline product, theproperties of which are shown in Table 8.

Comparative Example IV-1

The HCN-A heavy gasoline product obtained in Comparative Example I-1 wasmixed with the light gasoline fraction LCN-A to obtain a gasolineproduct, the properties of which are shown in Table 8.

Comparative Example IV-2

The HCN-B heavy gasoline product obtained in Comparative Example II-1was mixed with the light gasoline fraction LCN-B to obtain a gasolineproduct, the properties of which are shown in Table 8.

TABLE 8 Results of Examples IV-1 to IV-5 and Comparative Examples IV-1and IV-2 Example Nos. IV-1 IV-2 IV-3 IV-4 IV-5 Comp. Ex. IV-1 Comp. Ex.IV-2 Name of the aromatization MP051 MP051 MP051 MP051 MP051 None Nonecatalyst Type of the aromatization Passivated Aged Fresh Mixed Mixed / /catalyst Type of the gasoline A A A A A A B feedstock Etherification ofthe light No No No No No No No gasoline fraction (Yes/No) Gasoline yieldrelative to 99 99 98 98.9 98.9 99.3 99.3 the feedstock, % Density at 20°C., kg/m³ 740.6 740.6 740.8 740.6 740.6 740.1 739.1 Refractive index at20° C. 1.4146 1.4146 1.4131 1.4146 1.4146 1.4146 1.4129 Vapor pressure(RVPE), 70 70 83 71 71 60 58 kPa Carbon content, % (w) 85.84 85.84 85.9585.84 85.84 85.84 85.81 Hydrogen content, % (w) 14.16 14.16 14.05 14.1614.16 14.16 14.19 Sulfur content, mg/L 15 14 13 15 14 14 11 Nitrogencontent, mg/L 57 55 55 57 55 55 20 Benzene, % (by volume) 0.3 0.3 0.30.3 0.3 0.3 0.5 Group composition (FIA method) Aromatics, % (by volume)19.2 19.1 19.3 19.2 19.1 18.7 22.15 Olefins, % (by volume) 27.5 27.822.8 27 27 31.45 20.65 Saturated hydrocarbons, % 53.3 53.1 57.9 53.853.9 49.85 57.2 (by volume) Oxygen content, % (by / / / / / / / mass)Measured RON 89.3 89.3 88.2 89.2 89.2 88 87.4 Measured MON 78.5 78.578.2 78.5 78.5 78.2 78.1 (RON + MON)/2 83.9 83.9 83.2 83.85 83.85 83.182.75 Change in antiknock index −1 −1 −1.7 −1.05 −1.05 −1.8 −0.95Distillation range under normal pressure, ° C. IBP 35 35 32 35 35 42 41 5% (φ) 53.7 54 52 53.7 54 55 55 10% (φ) 62 62 60 62 62 64 62 30% (φ)80.6 81 82 80.6 81 81 75 50% (φ) 99.1 99 98 99.1 99 99 100 70% (φ) 127.7128 126 127.7 128 128 131 90% (φ) 173 173 172 173 173 173 171 FBP 205204 204 205 204 204 203

As shown in Table 8, in the case where a heavy gasoline product wasmixed with the light gasoline fraction to obtain a gasoline product,only the octane number (antiknock index) of the gasoline productsobtained in Comparative Examples IV-1 and IV-2 using the adsorptiondesulfurization catalyst FCAS alone was significantly lowered ascompared to the gasoline feedstock. The octane number of the gasolineproducts obtained in Examples IV-1 to IV-5 using a mixed catalystcomprising the adsorption desulfurization catalyst FCAS and thearomatization catalyst MP051 was improved as compared to ComparativeExample IV-1. Particularly, when an aromatization catalyst comprising apassivated or aged MP051 catalyst was used, the improvement was moreremarkable.

In addition, when comparing the results shown in Tables 7 and 8, it canbe seen that, in working examples comprising an etherification of thelight gasoline fraction, the octane number of the resulting gasolineproduct was significantly improved, its olefin content was significantlylowered, and its vapor pressure was effectively controlled, andmeanwhile the yield of gasoline was also increased to some extent, ascompared to working examples that did not comprise the etherification ofthe light gasoline fraction. Thus, in the case where a mixed catalystwas used in combination with an etherification treatment, a gasolineproduct having a low sulfur content, a low olefin content, a low vaporpressure, and a high octane number can be obtained in a high yield.

In the above specification, the inventive concept of the presentapplication has been described with reference to specific embodiments.However, it will be understood by those skilled in the art that variousmodifications and changes can be made without departing from the scopeof the present application. Accordingly, the specification and drawingsshould be considered to be illustrative rather than limiting, and allsuch modifications and changes should be covered by the presentinvention.

It is to be understood that some features described herein separately indifferent embodiments may be combined in a single embodiment. Meanwhile,some features described herein in a single embodiment for the sake ofbrevity may also be provided separately or in any sub-combination indifferent embodiments.

The invention claimed is:
 1. A process for treating gasoline,comprising: 1) splitting a gasoline feedstock into a light gasolinefraction and a heavy gasoline fraction; 2) optionally, subjecting atleast a portion of the resulting light gasoline fraction toetherification to obtain an etherified oil; and 3) contacting theresulting heavy gasoline fraction with a mixed catalyst and subjectingit to desulfurization and aromatization in the presence of hydrogen toobtain a heavy gasoline product; wherein the mixed catalyst comprises anadsorption desulfurization catalyst and an aromatization catalyst, andwherein the aromatization catalyst comprises at least about 50 wt % ofpassivated aromatization catalyst and/or aged aromatization catalyst,and has a micro-activity within a range from about 20 to about
 55. 2.The process according to claim 1, further comprising the step of: 4)mixing at least a portion of the light gasoline fraction and/or at leasta portion of the etherified oil with at least a portion of the heavygasoline product to provide a gasoline product.
 3. The process accordingto claim 1, wherein the aromatization catalyst comprises fresharomatization catalyst and passivated aromatization catalyst, whereinthe passivated aromatization catalyst is produced by contacting thearomatization catalyst with a compound containing carbon, sulfur and/ornitrogen to conduct a passivation reaction.
 4. The process according toclaim 1, wherein the aromatization catalyst comprises fresharomatization catalyst and aged aromatization catalyst, wherein the agedaromatization catalyst is produced by treating fresh aromatizationcatalyst at a temperature within a range from about 500 to about 800° C.for an aging time within a range from about 1 to about 360 hours and inan aging atmosphere containing steam.
 5. The process according to claim1, wherein the gasoline feedstock has at least one of the followingcharacteristics: 1) an olefin content of greater than about 20% byvolume; 2) a sulfur content of about 10 μg/g or above; 3) being at leastone selected from the group consisting of catalytic cracking gasoline,deep catalytic cracking gasoline, coker gasoline, thermal crackinggasoline, and straight-run gasoline, or a fraction thereof.
 6. Theprocess according to claim 1, wherein the split point between the lightgasoline fraction and the heavy gasoline fraction is within a range fromabout 60 to about 80° C.
 7. The process according to claim 1, whereinthe etherification comprises the step of: contacting the light gasolinefraction with an alcohol to subject the olefin in the light gasolinefraction to an etherification reaction with the alcohol in the presenceof an etherification catalyst, to obtain the etherified oil, wherein theetherification is carried out under the following conditions: atemperature within a range from about 20 to about 200° C., a pressurewithin a range from about 0.1 to about 5 MPa, a weight hourly spacevelocity within a range from about 0.1 to about 20 h⁻¹, and a molarratio of the alcohol to the light gasoline fraction within a range ofabout 1:(0.1-100); and the etherification catalyst comprises at leastone selected from the group consisting of resins, molecular sieves, andheteropolyacids.
 8. The process according to claim 1, wherein thedesulfurization and aromatization are carried out in a fluidizedreactor, wherein the fluidized reactor is at least one selected from thegroup consisting of riser reactors and dense phase fluidized reactors.9. The process according to claim 1, wherein the adsorptiondesulfurization catalyst comprises silica, alumina, zinc oxide, and adesulfurization active metal, and the desulfurization active metal is atleast one selected from the group consisting of cobalt, nickel, copper,iron, manganese, molybdenum, tungsten, silver, tin and vanadium.
 10. Theprocess according to claim 9, wherein on the basis of oxides, the zincoxide is present in an amount ranging from about 10% to about 90% byweight, the silica is present in an amount ranging from about 5% toabout 85% by weight, and the alumina is present in an amount rangingfrom about 5 to 30% by weight based on the dry weight of the adsorptiondesulfurization catalyst; and on the elemental basis, thedesulfurization active metal is present in the adsorptiondesulfurization catalyst in an amount ranging from about 5% to about 30%by weight based on the dry weight of the adsorption desulfurizationcatalyst.
 11. The process according to claim 1, wherein, on dry basis,the aromatization catalyst comprises about 10% to about 30% by weight ofa molecular sieve, about 0% to about 20% by weight of an aromatizationactive metal oxide and about 50% to about 90% by weight of a support,based on the total weight of the aromatization catalyst; wherein themolecular sieve comprises a Y molecular sieve and/or an MFI structuralmolecular sieve, the aromatization active metal is at least one selectedfrom the group consisting of metal elements of Group IVB, metal elementsof Group VB, metal elements of Group VIB, metal elements of Group VIII,metal elements of Group IB, metal elements of Group IIB, and metalelements of Group IIIA, and the support comprises silica and/or alumina.12. The process according to claim 1, wherein the aromatization catalystcan be prepared from a starting material comprising about 15% to about60% by weight of a natural mineral, about 10% to about 30% by weight ofa precursor of an inorganic oxide binder, and about 20% to about 80% byweight of a MFI structural molecular sieve containing phosphorus andsupported metal, based on the dry weight of the starting material,wherein the MFI structural molecular sieve has a n(SiO₂)/n(Al₂O₃) ratioof greater than about 100; a phosphorus content, on the basis of P₂O₅,within a range from about 0.1% to about 5% by weight based on the dryweight of the molecular sieve; a supported-metal content, on the basisof oxides, within a range from about 0.5% to about 5% by weight based onthe dry weight of the molecular sieve; an A1 distribution parameterD(A1) satisfying 0.6≤D(A1)≤0.85; a supported-metal distributionparameter D(M) satisfying 2≤D(M)≤10; a mesopore volume percentage withina range from about 40% to about 80% relative to the total pore volume; apercentage of strong acid content relative to the total acid contentwithin a range from about 60% to about 80%; and a ratio of the Bronstedacid (B acid) content to the Lewis acid (L acid) content within a rangefrom about 15 to about
 80. 13. The process according to claim 12,wherein the supported metal is at least one of zinc, gallium and iron.14. The process according to claim 1, wherein the percentage of thearomatization catalyst relative to the mixed catalyst is within a rangefrom about 1% to 30% by weight.
 15. The process according to claim 1,wherein the desulfurization and aromatization are carried out under thefollowing conditions: a reaction temperature within a range from about350 to about 500° C., a weight hourly space velocity within a range fromabout 2 to about 50 h⁻¹, a reaction pressure within a range from about0.5 MPa to about 3.0 MPa, and a volume ratio of hydrogen to the heavygasoline fraction within a range from about 1 to about
 500. 16. Theprocess according to claim 1, wherein the aromatization catalystcomprises at least about 80 wt % of passivated aromatization catalystand/or aged aromatization catalyst.
 17. The process according to claim1, wherein the aromatization catalyst comprises at least about 90 wt %of passivated aromatization catalyst and/or aged aromatization catalyst.18. The process according to claim 1, wherein the aromatization catalystcomprises at least about 95 wt % of passivated aromatization catalystand/or aged aromatization catalyst.